Metallocenes containing aryl-substituted indenyl derivatives as ligands, process for their preparation, and their use as catalysts

ABSTRACT

A very effective catalyst system for the polymerization or copolymerization of olefins comprises a cocatalyst, preferably an aluminoxane or a supported aluminoxane, and a metallocene of the formula I ##STR1## in which, in the preferred form, M 1  in Zr or Hf, R 1  and R 2  are halogen or alkyl, R 3  is alkyl, R 4  to R 12  are alkyl or hydrogen and R 13  is a (substituted) alkylene or heteroatom bridge. The metallocenes, in particular the zirconocenes, produce polymers of very high molecular weight, in the case of prochiral monomers polymers of very high molecular weight, very high stereotacticity and very high melting point, at high catalyst activities in the industrially particularly interesting temperature range between 50 and 80° C. In addition, reactor deposits are avoided by means of supported catalyst systems.

This application is a continuation of Ser. No. 08/475,155 filed Jun. 7,1995 which issued as U.S. Pat. No. 5,770,753, which in turn is adivision of Ser. No. 08/083,816 filed on Jun. 28, 1993 which is nowabandoned.

The invention relates to novel metallocenes containing aryl-substitutedindenyl derivatives as ligands which can be used very advantageously ascatalysts components in the preparation of polyolefins of highisotacticity, narrow molecular-weight distribution and very highmolecular weight.

Polyolefins of high molecular weight are of particular importance forthe production of films, sheets or large hollow articles or moldings,such as, for example, pipes.

The literature discloses the preparation of polyolefins using solublemetallocene compounds in combination with aluminoxanes or othercocatalysts which, due to their Lewis acidity, are able to convert theneutral metallocene into a cation and stabilize it.

Soluble metallocene compounds based onbis(cyclopentadienyl)dialkylzirconiumor bis(cyclopentadienyl)zirconiumdihalide in combination with oligomeric aluminoxanes are capable ofpolymerizing ethylene in good activity and propylene in moderateactivity. Polyethylene having a narrow molecular-weight distribution andmoderate molecular weight is obtained. The polypropylene prepared inthis way is atactic and has a very low molecular weight.

The preparation of isotactic polypropylene is achieved with the aid ofethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride togetherwith an aluminoxane in a suspension polymerization (cf. EP 185 918). Thepolymer has a narrow molecular-weight distribution. A particulardisadvantage of this process in that, at industrially relevantpolymerization temperatures, only polymers having a very low molecularweight can be prepared.

A special preactivation method for the metallocene using an aluminoxanehas also been proposed, resulting in a significant increase in theactivity of the catalyst system and in a considerable improvement in thegrain morphology of the polymer (cf. DE 37 26 067). However, thepreactivation hardly increases the molecular weight at all.

Also known are catalysts based on ethylenebisindenylhafnium dichlorideand ethylenebis(4,5,6,7-tetrahydro-1-indenyl)hafnium dichloride andmethylaluminoxane, by means of which relatively high-molecular-weightpolypropylenes can be prepared by suspension polymerization (cf. J. Am.Chem. Soc. (1987), 109, 6544). However, the grain morphology of thepolymers produced in this way under industrially relevant polymerizationconditions is unsatisfactory, and the activity of the catalyst systemsemployed is comparatively low. Together with the high catalysts costs,inexpensive polymerization using these systems is thus impossible.

A significant increase in the molecular weight has been achieved byusing metallocenes in which the aromatic π-ligands fixed by a bridgecarry substituents in the 2-position (cf. DE 40 35 886) or in the 2- and4-position (cf. DE 41 28 238).

A further increase in the molecular weight has been achieved by usingaromatic π-ligands containing substituents in the 2-, 4- and 6-position(cf. DE 41 39 596) and aromatic π-ligands of the 4,5-benzoindenyl type(cf. DE 41 39 595).

The last-mentioned metallocenes containing said substituents are alreadyvery effective in this respect at the polymerization temperature of 70°C. Nevertheless, the molecular weights which can be achieved at theindustrially optimum polymerization temperature of 70° C. are still toolow for many industrial applications, such as, for example, thepreparation of polymers for pipes and large hollow articles, and inparticular fibers.

Under the constraints of inexpensive large-scale production,polymerizations must be carried out at the highest possible reactiontemperature, since the heat of reaction produced at relatively highpolymerization temperatures can be dissipated using little coolingmedium. The cooling-water circuit can therefore be made significantlysmaller.

A disadvantage which frequently occurs in soluble (homogeneous)metallocene/methylaluminoxane catalyst systems in processes in which thepolymer is formed as a solid is the formation of thick deposits onreactor walls and stirrer. These deposits are formed by agglomeration ofthe polymer particles if the metallocene, or aluminoxane, or both, arein the form of a solution in the suspension medium. Deposits of thistype in the reactor systems must be removed regularly, since theyrapidly achieve considerable thicknesses, have high strength and hinderheat exchange with the cooling medium.

It is therefore advantageous to employ metallocenes in supported form.An efficient and simple process for supporting metallocenes which can beemployed universally in all polymerization processes has been proposed(cf. EP 92 107331.8).

A further disadvantage in the case of stereospecific polymerization ofprochiral monomers, for example of propylene, using metallocenecatalysts is the relatively low isotacticity, which results in lowmelting points in the case of isotactic polypropylene. In particularmetallocenes containing substituents in the 2- and 4-position andspecifically rac-dimethyl-silylbis(2-methyl-4-isopropylindenyl)zirconiumdichloride in combination with methylaluminoxane gives, in the case ofpropylene, a polymer of high isotacticity and thus high melting point(cf. DE 41 28 238). Nevertheless, the melting points which can beachieved are too low at industrially relevant polymerizationtemperatures (for example 70° C.) for some industrial applications.

However, there are also industrial applications in which low meltingpoints are desired.

The object was to find a process and/or a catalyst system which producespolymers of very high molecular weight and, in the case of isospecificpolymerization of prochiral monomers, polymers of high isotacticity inhigh yield. The use of a support would prevent the disadvantages knownfrom the prior art caused by deposit formation and a high proportion offine particles. The use of hydrogen as molecular weight regulator shouldthen enable the entire range of industrially interesting molecularweights to be covered by means of only a single metallocene.

It has been found that metallocenes containing specific indenylderivatives as ligands are suitable catalysts (catalyst components) inthe preparation of polyolefins of high molecular weight, in particularon use of prochiral monomers of isotactic polyolefins of very highmolecular weight and very high isotacticity.

Reaction of these soluble metallocenes with a supported organoaluminumcatalyst component gives a catalyst system which requires no additionalcocatalyst for activation and completely prevents formation of reactordeposits.

The present invention therefore relates to compounds of the formula I:##STR2## in which M¹ is a metal from group IVb, Vb or VIb of thePeriodic Table,

R¹ and R² are identical or different and are a hydrogen atom, a C₁ -C₁₀-alkyl group, a C₁ -C₁₀ -alkoxy group, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀-aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₇ -C₄₀ -alkylaryl group, a C₈ -C₁₀ -arylalkenyl group, an OH group or ahalogen atom, the radicals R³ are identical or different and are ahydrogen atom, a halogen atom, a C₆ --C₁₀ -alkyl group, which may behalogenated, a C₁ -C₁₀ -aryl group, an --NR¹⁶ ₂, --SR¹⁶, --OSiR¹⁶ ₃,--SiR¹⁶ ₃ or --PR¹⁶ ₂ radical, in which R¹⁶ is a halogen atom, a C₁ -C₁₀-alkyl group or a C₆ -C₁₀ -aryl group, R⁴ to R¹² are identical ordifferent and are as defined for R³, or adjacent radicals R⁴ to R¹²,together with the atoms connecting them, form one or more aromatic oraliphatic rings, or the radicals R⁵ and R⁸ or R¹², together with theatoms connecting them, form an aromatic or aliphatic ring,

R¹³ is ##STR3## ═BR¹⁴, ═AlR¹⁴, --Ge--, --O--, --S--, ═SO, ═SO₂, ═NR¹⁴,═CO, ═PR¹⁴ or ═P(O)R¹⁴, where R¹⁴ and R¹⁵ are identical or different andare a hydrogen atom, a halogen atom, a C₁ -C₁₀ -alkyl group, a C₁ --C₁₀-fluoroalkyl group, a C₁ -C₁₀ -alkoxy group, a C₁ -C₁₀ -aryl group, a C₁-C₁₀ -fluoroaryl group, a C₆ -C₁₀ -aryloxy group, a C₂ -C₁₀ -alkenylgroup, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀ -alkylaryl group or a C₈-C₄₀ -arylalkenyl group, or R¹⁴ and R¹⁵, in each case together withatoms connecting them, form one or more rings, and

M² is silicon, germanium or tin.

The present invention also relates to a process for the preparation ofan olefin polymer by polymerization or copolymerization of an olefin ofthe formula R^(a) --CH═CH--R^(b), in which R^(a) and R^(b) are identicalor different and are a hydrogen atom or a hydrocarbon radical having 1to 14 carbon atoms, or R^(a) and R^(b), together with the atomsconnecting them, may form one or more rings, at a temperature of from-60 to 200° C., at a pressure from 0.5 to 100 bar, in solution, insuspension or in the gas phase, in the presence of a catalyst formedfrom a metallocene as transition-metal compound and a cocatalyst,wherein the metallocene is a compound of the formula I.

The compounds according to the invention are metallocenes of the formulaI ##STR4## in which M¹ is a metal from group IVb, Vb or VIb of thePeriodic Table, for example titanium, zirconium, hafnium, vanadium,niobium, tantalum, chromium, molybdenum or tungsten, preferablyzirconium, hafnium or titanium.

R¹ and R² are identical or different and are a hydrogen atom, a C₁ -C₁₀-, preferably C₁ -C₁ -alkyl group, a C₁ -C₁₀ -, preferably C₁ -C₃-alkoxy group, a C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group, a C₆ -C₁₀ -,preferably C₆ -C₈ -aryloxy group, a C₂ -C₁₀ -, preferably C₂ -C₄-alkenyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₀ -arylalkyl group, a C₇-C₄₀ -, preferably C₇ -C₁₂ -alkylaryl group, a C₈ -C₄₀ -, preferably C₈-C₁₂ -arylalkenyl group, or a halogen atom, preferably chlorine.

The radicals R³ to R¹² are identical or different and are a hydrogenatom, a halogen atom, preferably fluorine, chlorine or bromine, a C₁-C₁₀ -, preferably C₁ -C₄ -alkyl group, which may be halogenated, a C₆-C₁₀ -, preferably C₆ -C₈ -aryl group, an --NR¹⁶ ₂, --SR¹⁶, --OSiR¹⁶ ₃,--SiR¹⁶ ₃ or --PR¹⁶ ₂ radical, where R¹⁶ can be a halogen atom,preferably chlorine, or a C₁ -C₁₀ -, preferably C₁ -C₄ -alkyl group or aC₆ -C₁₀ -, preferably C₆ -C₈ -aryl group.

The adjacent radicals R⁴ to R¹², together with the atoms connectingthem, can form an aromatic, preferably 6-membered aromatic or aliphatic,preferably 4-8-membered aliphatic ring.

R¹³ is ##STR5##

═BR¹⁴, ═AlR¹⁴, --Ge--, --O--, --S--, ═SO, ═SO₂, ═NR¹⁴, ═CO, ═PR¹⁴ or═P(O)R¹⁴, preferably ##STR6##

═BR¹⁴ , ═AlR¹⁴, --Ge--, --O--, --S--, ═SO, ═SO₂, ═CO, ═PR¹⁴ or ═P(O)R¹⁴,where R¹⁴ and R¹⁵ are identical or different and are a hydrogen atom, ahalogen atom, a C₁ -C₁₀ -, preferably a C₁ -C₄ -alkyl group, inparticular a methyl group, a C₁ -C₁₀ -fluoroalkyl group, preferably aCF₃ group, a C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group, a C₆ -C₁₀-fluoroaryl group, preferably a pentafluorophenyl group, a C₁ -C₁₀ -,preferably C₁ -C₄ -alkoxy group, in particular a methoxy group, a C₂-C₁₀ -, preferably C₂ -C₄ -alkenyl group, a C₇ -C₄₀ -, preferably C₇-C₁₀ -arylalkyl group, a C₈ -C₄₀ -, preferably C₈ -C₁₂ -arylalkenylgroup, a C₇ -C₄₀ -, preferably C₇ -C₁₂ -alkylaryl group, or R¹⁴ and R¹⁵,in each case with the atoms connecting them, form a ring.

M² is silicon, germanium or tin, preferably silicon or germanium.

For compounds of the formula I, it is preferred that

M¹ is zirconium or hafnium,

R¹ and R² are identical and are a C₁ -C₃ -alkyl group or a halogen atom,

the radicals R³ are identical and are a C₁ -C₄ -alkyl group, R⁴ to R¹²are identical or different and are hydrogen or a C₁ -C₄ -alkyl group,

R¹³ is ##STR7## where M² is silicon or germanium and R¹⁴ and R¹⁵ areidentical or different and a C₁ -C₄ -alkyl group or a C₁ -C₁₀ -arylgroup.

Preference is furthermore given to the compounds of formula I in whichthe radicals R⁴ and R⁷ are hydrogen, and R⁵, R⁶ and R⁸ to R¹² are a C₁-C₄ -alkyl group or hydrogen.

Particular preference is given to compounds of the formula I in which M¹is zirconium, R¹ and R² are identical and are chlorine, the radicals R³are identical and are a C₁ -C₄ -alkyl group, R⁴ and R⁷ are hydrogen, R⁵,R⁶ and R⁸ to R¹² are identical or different and are a C₁ -C₄ -alkylgroup or hydrogen, and R¹³ is ##STR8## where M² is silicon, and R¹⁴ andR¹⁵ are identical or different and are a C₁ -C₄ -alkyl group or a C₆-C₁₀ -aryl group.

The preparation of the metallocene I is carried out by processes knownfrom the literature and is shown in the reaction scheme below: ##STR9##

The 2-phenylbenzyl halide derivatives of the formula A are commerciallyavailable or can be prepared by methods known from the literature.

The conversion to the compounds of the formula B is carried out byreaction with substituted malonic esters under basic conditions, suchas, for example, in ethanolic solutions of sodium ethoxide.

The compounds of the formula B are hydrolyzed by means of alkali metalhydroxides, such as potassium hydroxide or sodium hydroxide, and theresultant dicarboxylic acids are decarboxylated by treatment at elevatedtemperature to give the compounds of formula C.

The ring closure to give the corresponding phenyl-1-indanones of theformula D is carried out by reaction with chlorinating reagents, suchas, for example, SOCl₂, to give the corresponding acid chlorides andsubsequent cyclization by means of a Friedel-Crafts catalyst in an inertsolvent, such as, for example, AlCl₃ or polyphosphoric acid in methylenechloride or CS₂.

The conversion to the 7-phenylindene derivatives of the formula E iscarried out by reduction using a hydride-transferring reagent, such as,for example, sodium borohydride or lithium aluminum hydride or hydrogenand an appropriate catalyst in an inert solvent, such as, for example,diethyl ether or tetrahydrofuran, to give the corresponding alcohols anddehydration of the alcohols under acidic conditions, such as, forexample, p-toluene-sulfonic acid or an aqueous mineral acid, or byreaction with dehydrating substances, such as magnesium sulfate,anhydrous copper sulfate or molecular sieve.

The preparation of the ligand systems of the formula G and theconversion to the bridged, chiral metallocenes of the formula H and theisolation of the desired racemic form are known in principle. To thisend, the phenylindene derivative of the formula E is deprotonated usinga strong base, such as, for example, butyllithium or potassium hydridein an inert solvent, and is reacted with a reagent of the formula F togive the ligand system of the formula G. This is subsequentlydeprotonation by means of two equivalents of a strong base, such as, forexample butyllithium or potassium hydride in an inert solvent, and isreacted with the appropriate metal tetrahalide, such as, for example,zirconium tetrachloride, in a suitable solvent. Suitable solvents arealiphatic or aromatic solvents, such as, for example, hexane or toluene,ethereal solvents, such as, for example, tetrahydrofuran or diethylether, or halogenated hydrocarbons, such as, for example, methylenechloride or halogenated aromatic hydrocarbons, such as, for example,o-dichlorobenzene. Separation of the racemic and meso forms is effectedby extraction or recrystallization using suitable solvents.

The derivatization to give the metallocenes of the formula I can becarried out, for example, by reaction with alkylating agents, such asmethyllithium.

Metallocenes I according to the invention are highly active catalystcomponents for the polymerization of olefins. The chiral metallocenesare preferably employed as racemates. However, it is also possible touse the pure enantiomers in the (+) or (-) form. The pure enantiomersallow an optically active polymer to be prepared. However, the meso formof the metallocenes should be removed, since the polymerization-activecenter (the metal atom) in these compounds is no longer chiral due tothe mirror symmetry at the central metal atom and it is therefore notpossible to produce a highly isotactic polymer. If the meso form is notremoved, atactic polymer is formed in addition to isotactic polymer. Forcertain applications, for example soft moldings, this may be entirelydesirable.

According to the invention, the cocatalyst used is preferably analuminoxane of the formula IIa for the linear type and/or of the formulaIIb for the cyclic type ##STR10## where, in the formulae IIa and IIb,the radicals R¹⁷ may be identical or different and are a C₁ -C₆ -alkylgroup, a C₆ -C₁₈ -aryl group, benzyl or hydrogen, and p is an integerfrom 2 to 50, preferably 10 to 35.

Radicals R¹⁷ are preferably identical and are preferably methyl,isobutyl, phenyl or benzyl, particularly preferably methyl.

If the radicals R¹⁷ are different, they are preferably methyl andhydrogen or alternatively methyl and isobutyl, where hydrogen orisobutyl is preferably present to the extent of 0.01-40% (number ofradicals R¹⁷).

The aluminoxane can be prepared in various ways by known processes. Oneof the methods is, for example, to react an aluminum hydrocarboncompound and/or a hydridoaluminum hydrocarbon compound with water (ingas, solid, liquid or bound form--for example as water ofcrystallization) in an inert solvent (such as, for example toluene). Inorder to prepare an aluminoxane containing different radicals R¹⁷, twodifferent trialkylaluminum compounds, for example, according to thedesired composition are reacted with water.

The precise structure of the aluminoxanes IIa and IIb is unknown.

Irrespective of the preparation method, all aluminoxane solutions havein common a varying content of unreacted aluminum starting compound,which is in free form or as an adduct.

It is possible to reactivate metallocene by means of aluminoxane of theformula IIa and/or IIb before use in the polymerization reaction. Thissignificantly increases the polymerization activity and improves thegrain morphology. Preactivation of the transition-metal compound iscarried out in solution. The metallocene is preferably dissolved in asolution of the aluminoxane in an inert hydrocarbon. Suitable inerthydrocarbons are aliphatic or aromatic hydrocarbons. Toluene ispreferred.

The concentration of the aluminoxane in the solution is in the rangefrom about 1% by weight to the saturation limit, preferably from 5 to30% by weight, in each case based on the total amount of solution. Themetallocene can be employed in the same concentration, but is preferablyemployed in an amount of from 10⁻⁴ to 1 mol per mol of aluminoxane. Thepreactivation is carried out for from 5 minutes to 60 hours, preferablyfor from 5 to 60 minutes. The temperature is -78 to 100° C., preferablyfrom 0 to 70° C.

The metallocene can be used to carry out a prepolymerization, preferablyusing the (or one of the) olefin(s) employed in the polymerization.

The metallocene can also be applied to a support. Suitable supportmaterials are, for example, silica gels, aluminum oxides, solidaluminoxane or other inorganic support materials, such as, for example,magnesium chloride. Another suitable support material is a polyolefinpowder in finely divided form.

It is preferred to apply the cocatalyst, i.e. the organoaluminumcompound, to a support, such as, for example, silica gels, aluminumoxides, solid aluminoxane, other inorganic support materials oralternatively a polyolefin powder in finely divided form, and then toreact it with the metallocene.

Inorganic supports which can be employed are oxides produced by flamepyrolysis by combustion of element halides in an oxyhydrogen flame, orcan be prepared as silica gels in certain particle size distributionsand particle shapes.

The preparation of the supported cocatalyst can be carried out, forexample, as described in EP 92 107 331.8 in the following way in anexplosion-proofed stainless-steel reactor with a 60 bar pump system,with inert-gas supply, temperature control by jacket cooling and secondcooling circuit via a heat exchanger on the forced-circulation system.The pump system aspirates the reactor contents via a connection in thereactor bottom and forces them into a mixer and back into the reactorthrough a rising line via a heat exchanger. The mixture is designed sothat the feed contains a narrowed tube cross section, where an increasedflow rate is produced and in whose turbulence zone a narrow feed line isinstalled axially and against the flow direction and which can befed--in cycles--in each case with a defined amount of water under 40 barof argon. The reaction is monitored via a sampler in the pump circuit.

In principle, however, other reactors are also suitable.

In the above-described reactor having a volume of 16 dm³, 5 dm³ ofdecane are introduced under inert conditions. 0.5 dm³ (=5.2 mol) oftrimethylaluminum are added at 25° C. 250 g of silica gel SD 3216-30(Grace AG) which had previously been dried at 120° C. in an argonfluidised bed are then metered into the reactor through a solids funneland homogeneously distributed with the aid of the stirrer and the pumpsystem. A total amount of 76.5 g of water is introduced to the reactorin portions of 0.1 cm³ every 15 seconds over the course of 3.25 hours.The pressure, caused by argon and the evolved gases, is kept constant at10 bar by a pressure-regulation valve. When all the water has beenintroduced, the pump system is switched off and the stirring iscontinued for a further 5 hours at 25° C.

The supported cocatalyst prepared in this way is employed as a 10%strength suspension in n-decane. The aluminum content is 1.06 mmol of Alper cm³ of suspension. The isolated solid contains 31% by weight ofaluminum, and the suspension medium contains 0.1% by weight of aluminum.

Further ways of preparing a supported cocatalyst are described in EP 92107331.8.

The metallocene according to the invention is then applied to thesupported cocatalyst by stirring the dissolved metallocene with thesupported cocatalyst. The solvent is removed and replaced by ahydrocarbon in which both the cocatalyst and the metallocene areinsoluble.

The reaction to give the supported catalyst system is carried out at atemperature of from -20 to +120° C., preferably at from 0 to 100° C.,particularly preferably at from 15 to 40° C. The metallocene is reactedwith the supported cocatalyst by combining the cocatalyst as a from 1 to40% strength by weight suspension, preferably with a from 5 to 20%strength by weight suspension, in an aliphatic, inert suspension medium,such as n-decane, hexane, heptane or diesel oil, with a solution of themetallocene in an inert solvent, such as toluene, hexane, heptane ordichloromethane, or with the finely ground solid of the metallocene.Conversely, it is also possible to react a solution of the metallocenewith the solid of the cocatalyst.

The reaction is carried out by vigorous mixing, for example by stirringat a molar Al/M¹ ratio of from 100/1 to 10,000/1, preferably from 100/1to 3,000/1, and for a reaction time of from 5 to 120 minutes, preferablyfrom 10 to 60 minutes, particularly preferably from 10 to 30 minutes,under inert conditions.

During the reaction time for the preparation of the supported catalystsystem, in particular on use of metallocenes according to the inventionhaving absorption maxima in the visible region, changes in the color ofthe reaction mixture occur which can be used to monitor the progress ofthe reaction.

When the reaction time is complete, the supernatant solution isseparated off, for example by filtration or decanting. The solid whichremains is washed from 1 to 5 times with an inert suspension medium,such as toluene, n-decane, hexane, diesel oil or dichloromethane, inorder to remove soluble constituents in the catalyst formed, inparticular to remove unreacted and thus soluble metallocene.

The supported catalyst system prepared in this way can be dried in vacuoas a powder or resuspended with adhering solvent and metered into thepolymerization system as a suspension in one of the abovementioned inertsuspension media.

According to the invention, compounds of the formulae R¹⁸ _(x) NH_(4-x)BR¹⁹ ₄, R¹⁸ _(x) PH_(4-x) BR¹⁹ ₄, R¹⁸ ₃ CBR¹⁹ ₄ and BR¹⁹ ₃ can be usedas suitable cocatalysts in place of or in addition to an aluminoxane. Inthese formulae, x is a number from 1 to 4, preferably 3, the radicalsR¹⁸ are identical or different, preferably identical, and are C₁ -C₁₀-alkyl, C₆ -C₁₈ -aryl or 2 radicals R¹⁸, together with the atomconnecting them, form a ring, the radicals R¹⁹ are identical ordifferent, preferably identical, and are C₆ -C₁₈ -aryl, which may besubstituted by alkyl, haloalkyl or fluorine. In particular, R¹⁸ isethyl, propyl, butyl or phenyl and R¹⁹, phenyl, pentafluorophenyl,3,5-bistrifluoromethylphenyl, mesityl, xylyl or tolyl (cf. EP 277 003,EP 277 004 and EP 426 638).

If the abovementioned cocatalysts are used, the actual (active)polymerization catalyst comprises the product of the reaction of themetallocene and one of said compounds. For this reason, this reactionproduct is preferably prepared in advance outside the polymerizationreactor in a separate step using a suitable solvent.

In principle, the cocatalyst can be, according to the invention, anycompound which, due to its Lewis acidity, is able to convert the neutralmetallocene into a cation and stabilize the latter ("labilecoordination"). In addition, the cocatalyst or the anion formedtherefrom should not undergo any further reactions with the metallocenecation formed (cf. EP 427 697).

In order to remove catalyst poisons present in the olefin, purificationusing an alkylaluminum compound, for example trimethylaluminum ortriethylaluminum, is advantageous. This purification can be carried outeither in the polymerization system itself, or the olefin is broughtinto contact with the Al compound before introduction into thepolymerization system and is subsequently removed again.

The polymerization or copolymerization is carried out in a known mannerin solution, in suspension or in the gas phase, continuously orbatchwise, in one or more steps, at a temperature of from -60 to 200°C., preferably from 30 to 80° C., particularly preferably from 50 to 80°C. The polymerization or copolymerization is carried out using olefinsof the formula R^(a) --CH--CH--R^(b). In this formula, R^(a) and R^(b)are identical or different and are a hydrogen atom or an alkyl radicalhaving 1 to 14 carbon atoms. However, R^(a) and R^(b) may alternativelyform a ring together with the carbon atoms connecting them. Examples ofsuch olefins are ethylene, propylene, 1-butene, 1-hexene,4-methyl-1-pentene, 1-octene, norbornene and norbornadiene. Inparticular, propylene and ethylene are polymerized.

If necessary, hydrogen is added as a molecular-weight regulator and/orin order to increase the activity. The overall pressure polymerizationsystem is from 0.5 to 100 bar. Polymerization is preferably carried outin the industrially particularly interesting pressure range from 5 to 64bar.

The metallocene is used in the polymerization in a concentration, basedon the transition metal, of from 10⁻³ to 10⁻⁸ mol, preferably from 10⁻⁴to 10⁻⁷ mol, of transition metal per dm³ of solvent or per dm³ ofreactor volume. The aluminoxane is used in a concentration of from 10⁻⁵to 10⁻¹ mol, preferably from 10⁻⁴ to 10⁻² mol, per dm³ of solvent or perdm³ of reactor volume. The other cocatalysts mentioned are used in anapproximately equimolar amount with respect to the metallocene. Inprinciple, however, higher concentrations are also possible.

If the polymerization is carried out as a suspension or solutionpolymerization, an inert solvent which is customary for the Zieglerlow-pressure process is used. For example, the polymerization is carriedout in an aliphatic or cycloaliphatic hydrocarbon; examples which may bementioned are propane, butane, hexane, heptane, isooctane, cyclohexaneand methylcyclohexane. It is furthermore possible to use a benzine orhydrogenated diesel oil fraction. Toluene can also be used. Thepolymerization is preferably carried out in the liquid monomer.

If inert solvents are used, the monomers are metered in in gas or liquidform.

The polymerization can have any desired duration, since the catalystsystem to be used according to the invention exhibits only a slighttime-dependent drop in polymerization activity.

Before addition of the catalyst, in particular of the supported catalystsystem (comprising a metallocene according to the invention and asupported cocatalyst or a metallocene according to the invention and anorganoaluminum compound on a polyolefin powder in finely divided form),another alkylaluminum compound, such as, for example, trimethylaluminum,triethylaluminum, triisobutylaluminum, trioctylaluminum orisoprenylaluminum, may additionally be introduced into the reactor inorder to render the polymerization system inert (for example to removecatalyst poisons present in the olefin). This compound is added to thepolymerization system in a concentration of from 100 to 0.01 mmol of Alper kg of reactor contents. Preference is given to triisobutylaluminumand triethylaluminum in a concentration of from 10 to 0.1 mmol of Al perkg of reactor contents. This allows the molar Al/M¹ ratio to be selectedat a low level in the synthesis of a supported catalyst system.

In principle, however, the use of further substances for catalysis ofthe polymerization reaction is unnecessary, i.e. the systems accordingto the invention can be used as the only catalysts for thepolymerization of olefins.

The process according to the invention is distinguished by the fact thatthe metallocenes described give polymers of very high molecular weight,in the case of prochiral monomers very high molecular weight and veryhigh stereotacticity, with high catalyst activities in the industriallyparticularly interesting temperature range from 50 to 80° C.

In particular, the zirconocenes according to the invention aredistinguished by the fact that, in the case of stereospecificpolymerization of prochiral olefins, for example polypropylene, polymersof high isotacticity are obtained.

In particular in the case of isospecific polymerization of propylene,isotactic polypropylene having long isotactic sequence lengths and highmelting point are obtained.

In addition, the catalyst systems supported according to the inventionprevent reactor deposits.

The examples below serve to illustrate the invention in greater detail.

All glass equipment was dried by heating in vacuo and was flushed withargon. All operations were carried out in Schlenk vessels with exclusionof moisture and oxygen. The solvents used were in each case freshlydistilled over Na/K alloy under argon and stored in Schlenk vessels.

The determination of the Al/CH₃ ratio in the aluminoxane was carried outby decomposition of the sample using H₂ SO₄ and determination of thevolume of the resultant hydrolysis gases under standard conditions andby complexometric titration of the aluminum in the sample, thendissolved, by the Schwarzenbach method.

For Example Nos. 3 to 5 with the supported aluminum compound(methylaluminoxane on silica gel), referred to below as "MAO on SiO₂ ",an approximately 10% strength by weight suspension in n-decane wasprepared, containing, according to aluminum determination, 60 mg ofAl/cm³.

For Examples 26 to 30 with the supported aluminum compound(methylaluminoxane on silica gel SD 3216-30/Grace), referred to below as"FMAO on SiO₂ ", a solvent-free powder was used containing 20% by weightof aluminum in the solid.

Toluene-soluble methylaluminoxane was employed as a 10% strength byweight toluene solution for the examples for suspension polymerizationand for bulk polymerization with unsupported metallocene and contained,according to aluminum determination, 36 mg of Al/cm³. The mean degree ofoligomerization, according to freezing point depression in benzene, wasn=20. For the toluene-soluble methylaluminoxane, an Al:CH₃ ratio of1:1.55 was determined.

The following abbreviations are used:

    ______________________________________                                        VI =        viscosity index in cm.sup.3 /g                                      M.sub.w = weight average molecular weight in g/mol                             (determined by gel permeation                                                 chromatography)                                                              M.sub.w /M.sub.n = molecular weight dispersity                                M.p. = melting point in ° C. (determined by DSC,                        heating/cooling rate 20° C./min)                                      II = Isotactic index (II = mm + 1.2 mr, deter-                                 mined by .sup.13 C-NMR spectroscopy)                                         MFI 230/5 = meltflow index, measured in accordance                             with DIN 53735, in dg/min                                                    BD = polymer bulk density in g/dm.sup.3.                                    ______________________________________                                    

Synthesis of the metallocenes I used in the polymerization examples (thestarting materials employed are commercially available):

A. rac-Dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride(5) 1. (±)-2-(2-Phenylbenzyl)propionic Acid (1)

48.6 g (0.279 mol) of diethylmethyl malonate were added dropwise at roomtemperature to 6.5 g (0.285 mol) of sodium in 160 cm³ of H₂ O-free EtOH.70.4 g (0.285 mol) of 2-phenylbenzyl bromide in 20 cm³ of H₂ O-free EtOHwere subsequently added dropwise, the batch was refluxed for 3 hours.The solvent was stripped off, and 200 cm³ of H₂ O were added to theresidue. The organic phase was separated off, and the aqueous phase wassaturated with NaCl and extracted twice with 200 cm³ of Et₂ O in eachcase. The organic phase combined with the extracts was dried (MgSO₄).

The residue remaining after the solvent had been stripped off was takenup in 500 cm³ of EtOH and 50 cm³ of H₂ O, and 56 g (1 mol) of KOH wereadded. The reaction mixture was refluxed for 4 hours. The solvent wasstripped off in vacuo, the residue was taken up in 500 cm³ of H₂ O, andthe solution was acidified to pH 1 by means of concentrated aqueous HCl.The precipitate which deposited was filtered off with suction and heatedfor 30 minutes at 250° C. in a bulb tube with vigorous foaming, giving58.3 g (85%) of 1 as a viscous oil.

¹ H-NMR (100 MHz, CDCl₃): 11.7 (s, 1H, COO), 7.1-7.5 (m, 9H, arom. H)2.3-3.2 (m, 3H, CH and CH₂), 0.9 (d, 3H, CH₃).

2. (±)-2-Methyl-4-phenylindan-1-one (2)

A solution of 58 g (0.242 mol) of 1 in 60 cm³ (0.83 mol) of thionylchloride was stirred at room temperature for 18 hours. Excess thionylchloride was removed at 10 mbar, and the oily residue was freed fromadhering residues of thionyl chloride by repeated dissolution in 100 cm³of toluene in each case and stripping off in vacuo.

The acid chloride was taken up in 150 cm³ of toluene and added dropwiseat 10° C. to a suspension of 48 g (0.363 mol) of AlCl₃ in 400 cm³ oftoluene. When the addition was complete, the mixture was refluxed for afurther 3 hours. The reaction mixture was poured into 500 g of ice andacidified to pH 1 by means of concentrated aqueous HCl. The organicphase was separated off, the aqueous phase was then extracted threetimes with 100 cm³ of Et₂ O in each case. The combined organic phaseswere washed with saturated aqueous NaHCO₃ solution and saturated aqueousNaCl solution and then dried (MgSO₄), giving 50.4 g (93%) of 2, whichwas reacted further without further purification.

¹ H-NMR (100 MHz, CDCl₃): 7.2-7.8 (m, 8H, arom. H), 3.3 (dd, 1H, β-H),2.5-2.9 (m, 2H, α- and β-H), 1.3 (d, 3H, CH₃).

3. 2-Methyl-7-phenylindene (3)

50 g (0.226 mmol) of 2 were dissolved in 450 cm³ of THF/MeOH (2:1), and12.8 g (0.34 mol) of sodium borohydride were added in portions at 0° C.with stirring. The reaction mixture was stirred for a further 18 hoursand poured into ice, concentrated HCl was added to pH 1 and the mixturewas extracted a number of times with Et₂ O. The combined organic phaseswere washed with saturated aqueous NaHCO₃ solution and NaCl solution andthen dried (MgSO₄). The solvent was removed in vacuo, and the crudeproduct, without further purification, was taken up in 1 dm³ of toluene,2 g of p-toluene sulfonic acid were added, and the mixture was refluxedfor 2 hours. The reaction mixture was washed with 200 cm³ of saturatedaqueous NaHCO₃ solution, and the solvent was removed in vacuo. The crudeproduct was purified by filtration through 500 g of silica gel(hexane/CH₂ Cl₂), giving 42 g (90%) of 3 as a colorless oil.

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.6 (m, 8H, arom. H), 6.5 (m, 1H,H--C(3)), 3.4 (s, 2H, CH₂), 2.1 (s, 3H, CH₃).

4. Dimethylbis(2-methyl-4-phenylindenyl)silane (4)

29 cm³ (73 mmol) of a 2.5 M solution of butyllithium in hexane wereadded at room temperature under argon to a solution of 15 g (72.7 mmol)of 3 in 200 cm³ of H₂ O- and O₂ -free toluene and 10 cm³ of H₂ O- and O₂-free THF and heated at 80° C. for 1 hour. The batch was subsequentlycooled to 0° C., and 4.7 g (36.4 mmol) of dimethyldichlorosilane wereadded. The mixture was heated at 80° C. for 1 hour and subsequentlypoured into 100 cm³ of H₂ O. The mixture was extracted a number of timeswith Et₂ O, and the combined organic phases were dried (MgSO₄). Thecrude product remaining after the solvent had been stripped off waschromatographed on 300 g of silica gel (hexane/CH₂ Cl₂), giving 12.0 g(70%) of 4.

¹ H-NMR (100 MHz, CDCl₃): 7.10-7.70 (m, 16H, arom. H), 6.80 (m, 2H,H--C(3)), 3.80 (s, 2H, H--C(1)), 2.20 (m, 6H, CH₃) -0.20 (m, 6H, CH₃Si).

5. rac-Dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride(5)

10.6 cm³ (26 mmol) of a 2.5 M solution of butyllithium in hexane wereadded at room temperature under argon to a solution of 6.0 g (12.9 mmol)of 4 in 100 cm³ of H₂ O- and O₂ -free toluene, and the mixture wasrefluxed for 3 hours. The suspension of the dilithio salt wassubsequently cooled to -25° C., and 3.2 g (13.6 mmol) of zirconiumtetrachloride were added. The batch was warmed to room temperature overthe course of 1 hour, stirred for a further hour and then filteredthrough a G3 frit. The residue was extracted with 50 cm³ of toluene, andthe combined filtrates were freed from solvent under an oil-pump vacuum,giving 9.0 g of the metallocene in the form of a yellow powder as amixture of the racemic and meso forms in the ratio 1:1. Pure racemate(5) was isolated by stirring the crude mixture a number of times with 20cm³ of methylene chlorine in each case, the racemate remaining as ayellow crystal powder and the meso form being washed out. 2.74 g (33%)of the pure racemate were obtained.

¹ H-NMR (300 MHz, CDCl₃): 7.0-7.7 (m, 16H, arom. H), 6.9 (s, 2H,H--C(3)), 2.2 (s, 6H, CH₃), 1.3 (m, 6H, CH₃ Si). Molecular weight: 626M⁺, correct decomposition pattern.

EXAMPLE Brac-Methylphenylsilanediylbis-(2-methyl-4-phenylindenyl)zirconiumdichloride (7) 1. Methylphenylbis-(2-methyl-4-phenylindenyl)silane (6)

21 ml (52 mmol) of a 2.5 M solution of butyllithium in hexane were addedat room temperature under argon to a solution of 10.3 g (50 mmol) of 3in 90 ml of H₂ O- and O₂ -free toluene and 10 ml of H₂ O- and O₂ -freeTHF. The mixture was heated at 80° C. for 1 hour and subsequently cooledto 0° C. 4.8 g (25 mmol) of methylphenyldichlorosilane were added, andstirring was continued overnight at room temperature. The precipitatedLiCl was separated off by filtration, and the crude product remainingafter the solvent had been stripped off in vacuo was chromatographed on300 g of silica gel (hexane/CH₂ Cl₂ 9:1), giving 4.6 g (35%) of 6.

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.8 (m, 16H, arom. H), 6.9 (m, 2H,H--C(3)), 3.9 (m, 2H, H--C(1)), 2.3 (m, 6H, CH₃), -0.1 (s, 3H, CH₃ Si).

2. rac-Methylphenylsilanediylbis(2-methyl-4-phenylindenyl)zirconiumDichloride (7)

3.6 ml (8.9 mmol) of a 2.5 M solution of butyllithium in hexane wereadded at room temperature under argon to 2.3 g (4.4 mmol) of 6 in 25 mlof H₂ O- and O₂ -free toluene, and the mixture was heated at 80° C. for3 hours. The suspension of the dilithio salt was subsequently cooled to-30° C., and 1.1 g (4.5 mmol) of zirconium tetrachloride were added. Themixture was warmed to room temperature over the course of 1 hour andstirred for a further 1 hour. After filtration through a G3 frit, thesolvent was removed from the filtrate, and the residue was crystallizedfrom 10 ml of methylene chloride, giving 0.2 g of the racemic form of 7as orange crystals.

¹ H-NMR (100 MHz, CDCl₃): 7.0-8.2 (m, 21H, arom. H), 6.9 (m, 2H,H--C(3)), 2.4 (s, 3H, CH₃), 2.0 (s, 3H, CH₃), 1.3 (s, 3H, CH₃ Si). Massspectrum: 690 M⁺, correct decomposition pattern.

EXAMPLE C rac-Dimethylsilandiylbis(4-phenylindenyl)zirconium Dichloride(12) 1. 3-(2-Phenylphenyl)propionic Acid (8)

93 cm³ (0.61 mmol) of diethyl malonate dissolved in 50 cm³ of H₂ O-freeEtOH were added dropwise at room temperature to 14 g (0.61 mmol) ofsodium in 400 cm³ of H₂ O-free EtOH. 150 g (0.61 mmol) of 2-phenylbenzylbromide in 200 cm³ of H₂ O-free EtOH were subsequently added dropwise,and the mixture was refluxed for 3 hours. 102 g (1.83 mol) of KOHdissolved in 150 cm³ of H₂ O were added at room temperature, and themixture was refluxed for a further 4 hours. The solvent was removed invacuo, H₂ O was added to the residue until the latter dissolvedcompletely, and the mixture was acidified to pH 1 by means ofconcentrated aqueous HCl. The precipitate which formed was filtered offwith suction, dried and heated at 130° C. for 1 hour, giving 112 g (81%)of 8 as a viscous oil.

¹ H-NMR (100 MHz, CDCl₃): 9.1 (s, 1H, COOH), 6.9-7.5 (m, 9H, arom. H),2.3-3.0 (m, 4H, 2CH₂).

2. 4-Phenyl-1-indanone (9)

A solution of 102 g (0.45 mol) of 8 in 37 cm³ (0.5 mol) of thionylchloride was stirred at room temperature for 18 hours. Excess thionylchloride was removed at 10 mbar, and the oily residue was freed fromadhering residues of thionyl chloride by repeated dissolution in 100 cm³of toluene in each case and stripping off the toluene in vacuo.

The acid chloride was taken up in 200 cm³ of toluene and added dropwiseat 10° C. to a suspension of 72 g (0.54 mol) of AlCl₃ in 1000 cm³ oftoluene. The reaction mixture was heated at 80° C. for 1 hour, pouredinto 1000 g of ice and acidified to pH 1 by means of concentratedaqueous HCl.

The organic phase was separated off, and the aqueous phase was thenextracted 3 times with 200 cm³ of Et₂ O in each case. The combinedorganic phases were washed with saturated aqueous NaHCO₃ solution andsaturated aqueous NaCl solution and subsequently dried (MgSO₄), giving96 g (96%) of 9, which was reacted further without further purification.

¹ H-NMR (100 MHz, CDCl₃): 6.9-7.5 (m, 8H, arom. H), 2.5-3.4 (m, 4H,2CH₂).

3. 7-Phenylindene (10)

23 g (0.62 mol) of NaBH₄ were added in portions at 0° C. to a solutionof 86 g (0.41 mol) of 9 in 300 cm³ of THF/methanol 2:1. The reactionmixture was stirred at room temperature for 18 hours and poured into 300g of ice, concentrated aqueous HCl was added to pH 1, and the mixturewas extracted a number of times with Et₂ O. The combined organic phaseswere washed with saturated aqueous NaHCO₃ solution and saturated aqueousNaCl solution, dried (MgSO₄) and freed from solvent in vacuo.

The crude product was taken up in 1000 cm³ of toluene, 4.5 g ofp-toluenesulfonic acid were added, the reaction mixture was refluxed for2 hours on a water separator and washed three times with 250 cm³ ofsaturated aqueous NaHCO, solution, and the solvent was removed in vacuo.Distillation at 0.1 mbar gave, at 96-108° C., 33 g (41%) of 10 as acolorless oil.

¹ H-NMR (100 MHz, CDCl₃): 7.1-7.7 (m, 8H, arom. H), 6.9 and 6.5 (2m, 2H,CH), 3.5 (m, 2H, CH₂).

4. Dimethylbis(4-phenylindenyl)silane (11)

18.7 cm³ (50 mmol) of a 20% strength solution of butyllithium in toluenewere added at room temperature to a solution of 10 g (50 mmol) of 10 in100 cm³ of H₂ O- and O₂ -free toluene and 5 ml of H₂ O- and O₂ -freeTHF, and the mixture was heated at 80° C. for 2 hours. The yellowsuspension was subsequently cooled to 0° C., and 3.2 g (25 mmol) ofdimethyldichlorosilane were added. The reaction mixture was heated at80° C. for a further 1 hour and subsequently washed with 50 cm³ of H₂ O.The solvent was removed in vacuo, and the residue was recrystallizedfrom heptane at -20° C., giving 6.7 g (62%) of 11 as colorless crystals(m.p. 109-110° C).

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.7 (m, 18H, arom. H and H--C(3)), 6.8(dd, 2H, H--C(2)), 3.8 (m, 2H, H--C(1)), -0.2, (s, 6H, CH₃ Si).

5. rac-Dimethylsilanediylbis(4-phenylindenyl)zirconium Dichloride (12)

12 cm³ (32 mmol) of a 20% strength solution of butyllithium in toluenewere added at room temperature under argon to a solution of 6.6 g (16mmol) of 11 in 70 cm³ of H₂ O- and O₂ -free Et₂ O, and the mixture wassubsequently refluxed for 3 hours. The solvent was removed in vacuo, theresidue was filtered through a G3 Schlenk frit with 50 ml of H₂ O- andO₂ -free hexane, washed with 50 ml of H₂ O- and O₂ -free hexane anddried (0.1 mbar, RT).

The dilithio salt was added at -78° C. to a suspension of 3.6 g (16mmol) of zirconium tetrachloride in 80 cm³ of methylene chloride, andthe mixture was warmed to room temperature over the course of 18 hourswith magnetic stirring. The batch was filtered through a G3 frit, andthe residue was then extracted in portions with a total of 200 cm³ ofmethylene chloride. The combined filtrates were freed from solvent invacuo and recrystallized from methylene chloride/hexane (1:1). 5.6 g ofthe racemic and meso forms in the ratio 1:1 were obtained. Furtherrecrystallization from methylene chloride gave the racemic complex inthe form of yellow crystals.

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.8 (m, 22 H, arom. H and H--C(3)), 6.1(d, 2H, H--C(2)), 1.1 (a, 6H, CH₃ Si). Mass spectrum: 598 M⁺, correctdecomposition pattern.

EXAMPLE D rac-Dimethylsilanediylbis(2-ethyl-4-phenylindenyl)zirconiumDichloride (17) 1. (±)-2-(2-phenylbenzyl)butyric Acid (13)

188 g (1 mol) of diethyl ethylmalonate dissolved in 100 cm³ of H₂ O-freeEtOH are added dropwise at room temperature to 23 g (1 mol) of sodium in400 cm³ of H₂ O-free EtOH. 247 g (1 mol) of 2-phenylbenzyl bromide in300 cm³ of H₂ O-free EtOH were subsequently added dropwise, and themixture was refluxed for 3 hours. 170 g (3 mol) of KOH dissolved in 300cm³ of H₂ O were added at room temperature, and the mixture was refluxedfor a further 4 hours. The solvent was removed in vacuo, H₂ O was addedto the residue until the latter had dissolved completely, and themixture was subsequently acidified to pH 1 by means of concentratedaqueous HCl. The precipitate which formed was filtered off with suction,dried and heated at 130° C. for 1 hour, giving 236 g (93%) of 13 as aviscous oil.

¹ H-NMR (100 MHz, CDCl₃): 10.3 (s, 1H, COOH), 7.0-7.3 (m, 9H, arom. H),2.5-3.0 (m, 3H, CH and CH₂), 1.5-1.9 (m, 2H, CH₂), 0.9 (t, 3H, CH₃).

2. (±)-2-Ethyl-4-phenyl-1-indanone (14)

A solution of 236 g (0.93 mol) of 13 in 81 cm³ (1.2 mol) of thionylchloride was stirred at room temperature for 18 hours. Excess thionylchloride was removed at 10 mbar and the oily residue was freed fromadhering residues of thionyl chloride by repeated dissolution in 200 cm³of toluene in each case and stripping off in vacuo.

The acid chloride was taken up in 400 cm³ of toluene and added dropwiseat 10° C. to a suspension of 133 g (1.0 mol) of AlCl₃ in 2000 cm³ oftoluene. The reaction mixture was heated at 80° C. for 1 hour, pouredinto 2000 g of ice and acidified to pH 1 by means of concentratedaqueous HCl. The organic phase was separated off, and the aqueous phasewas then extracted three times with 200 cm³ of Et₂ O in each case. Thecombined organic phases were washed with saturated aqueous NaHCO₃solution and saturated aqueous NaCl solution and subsequently dried(MgSO₄), giving 187 g (85%) of 14, which was reacted further withoutfurther purification.

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.8 (m, 8H, atom. H), 3.1-3.4 (m, 1H,H--C(3)), 2.5-2.9 (m, 2H, H--C(2)) and H--C(3)), 1.3-2.0 (m, 2H, CH₂),0.9 (t, 3H, CH₃).

3. 2-Ethyl-7-phenylindene (15)

8 g (0.21 mol) of NaBH₄ were added in portions at 0° C. to a solution of50 g (0.21 mol) of 14 in 600 cm³ of THF/methanol 2:1, the reactionmixture was stirred at room temperature for 18 hours and poured into 600g of ice, concentrated aqueous HCl was added to pH 1, and the mixturewas extracted a number of times with Et₂ O. The combined organic phaseswere washed with saturated aqueous NaHCO₃ solution and saturated aqueousNaCl solution and subsequently dried (MgSO₄).

The crude product was taken up in 1000 cm³ of toluene, 4.5 g ofp-toluenesulfonic acid were added, the reaction mixture was refluxed for2 hours on a water separator and washed 3 times with 250 cm³ ofsaturated aqueous NaHCO, solution, and the solvent was removed in vacuo.Distillation at 0.1 mbar gave, at 135° C., 33 g (72%) of 15 as acolorless oil.

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.5 (m, BR, arom. H) 6.5 (m, 1H, CH), 3.2(m, 2H, CH₂), 2.5 (dq, 2H, CH₂), 1.1 (t, 3R, CH₃).

3. Dimethylbis(2-ethyl-4-phenylindenyl)silane (16)

29 cm³ (77 mmol) of a 20% strength solution of butyllithium in toluenewere added at room temperature to a solution of 17 g (77 mmol) of 15 in160 cm³ of H₂ O- and O₂ -free toluene and 8 ml of H₂ O- and O₂ -freeTHF, and the mixture was heated at 80° C. for 2 hours. The yellowsuspension was subsequently cooled to 0° C., and 5 g (38 mmol) ofdimethylchlorosilane were added. The reaction mixture was heated at 80°C. for a further 1 hour and subsequently washed with 100 cm³ of H₂ O.The solvent was removed in vacuo, and the residue was purified bychromatography on 200 g of silica gel (hexane/methylene chloride 9:1),giving 9 g (47%) of 16 as a viscous oil.

¹ H-NMR (100 MHz, CDCl₃): 6.97-7.4 (m, 16H, arom. H), 6.5 (m, 2H,H--C(3)), 3.7 (m, 2H, H--C(1)), 2.4 (m, 4H, CH₂), 1.1 (t, 6H, CH₃),-0.1, (s, 6H, CH₃ Si).

5. rac-Dimethylsilanediylbis(2-ethyl-4-phenylindenyl)zirconiumDichloride (17)

8.4 cm³ of 20% strength solution of butyllithium in toluene were addedat room temperature under argon to a solution of 5.6 g (11 mmol) of 16in 50 cm³ of H₂ O- and O₂ -free Et₂ O, and the mixture was subsequentlyrefluxed for 3 hours. The solvent was removed in vacuo, and the residuewas filtered through a G3 Schlenk frit with 50 ml of H₂ O- and O₂ -freehexane, then washed with 50 ml of H₂ O- and O₂ -free hexane and dried(0.1 mbar, RT).

The dilithio salt was added at -78° C. to a suspension of 2.5 g (11mmol) of zirconium tetrachloride in 50 cm³ of methylene chloride, andthe mixture was warmed to room temperature over the course of 18 hourswith magnetic stirring. The batch was filtered through a G3 frit, andthe residue was then extracted in portions with a total of 100 cm³ ofmethylene chloride. The combined filtrates were freed from solvent invacuo and recrystallized from toluene/hexane (1:1). 2 g (27%) of theracemic and meso forms in the ratio 1:1 were obtained. Furtherrecrystallization from toluene gave the racemic complex 17 in the formof yellow crystals.

¹ H-NMR (100 MHz, CDCl₃): 6.8-7.7 (m, 16H, arom. H), 6.6 (m, 2H,H--C(3)), 2.3-3.9 (m, 4H, CH₂) 1.0-1.4 (m, 12H, CH₃ and CH₃ Si). Massspectrum: 654 M⁺, correct decomposition pattern.

EXAMPLE E rac-Dimethylsilanediylbis (2-methyl-4-(1-naphthyl)indenyl)zirconium Dichloride (24) 1. 2-(1-Naphthyl)toluene(18)

13.9 g (0.57 mol) of magnesium turnings were covered by 150 ml of H₂O-free Et₂ O, and the Grignard reaction was initiated by means of 5 g of2-bromotoluene and a few grains of iodine. 93 g (0.57 mol) of1-bromotoluene in 450 ml of H₂ O -free Et₂ O were subsequently addeddropwise at such a rate that the reaction mixture was kept at the boil.When the addition was complete, boiling was continued until themagnesium had reacted fully.

The Grignard solution was subsequently added dropwise to a solution of118 g (0.57 mol) of 1-bromonaphthalene and 3.5 g ofbis(triphenylphosphine)nickel dichloride in 800 cm³ of toluene at such arate that the internal temperature did not exceed 50° C. The mixture wassubsequently refluxed for a further 3 hours, 500 ml of 10% strengthaqueous HCl were added, the phases were separated, and the organic phasewas freed from solvent in vacuo. Filtration through silica gel (hexane)gave 115 g (92%) of 18 as a colorless oil.

¹ H-NMR (100 MHz, CDCl₃): 7.2-8.0 (m, 11H, arom. H), 2.0 (s, 31, CH₃).

2. 2-(1-Naphthyl)benzyl bromide (19)

114 g (0.52 mol) of 18 and 103 g (0.58 mol) of N-bromosuccinimide weredissolved in 2000 cm³ of tetrachloromethane at room temperature, 3 g ofazobisisobutyronitrile were added, and the mixture was refluxed for 4hours. The succinimide which precipitated was filtered off, the solventwas removed in vacuo, and the residue was purified by filtration through1000 g of silica gel (hexane/methylene chloride 9:1), giving 141 g (82%)of 19 as a colorless lachrymatory oil.

¹ H-NMR (100 MHz, CDCl₃); 7.1-8.0 (m, 11H1, arom. H), 4.2 (q, 2H, CH₂Br).

3. (±)-2-(2-(1-naphthyl)benzyl)propionic acid (20)

75 g (0.43 mmol) of diethyl methylmalonate dissolved in 50 cm³ of H₂O-free EtOH were added dropwise at room temperature to 10 g (0.43 mmol)of sodium in 100 cm³ of H₂ O-free EtOH. 140 g (0.43 mmol) of2-phenylbenzyl bromide in 200 cm³ of H₂ O-free EtOH were subsequentlyadded dropwise, and the mixture was refluxed for 3 hours. 85 g (1.3 mol)of KOH dissolved in 100 cm³ of H₂ O were added at room temperature, andthe mixture was refluxed for a further 4 hours. The solvent was removedin vacuo, H₂ O was added to the residue until the latter had dissolvedcompletely, and the mixture was acidified to pH 1 by means ofconcentrated aqueous HCl. The precipitate which had formed was filteredoff with suction, dried and heated at 130° C. for 1 hour, giving 96 g(77%) of 20 as a viscous oil.

¹ H-NMR (100 MHz, CDCl₃): 10.1 (s, 1H, COOH), 6.9-8.0 (m, 11H, arom. H)2.3-3.0 (m, 3H, CH₂ and CH), 0.8 (d, 3H, CH₃) .

4. (±)-2-Methyl-4-(1-naphthyl)-1-indanone (21)

A solution of 96 g (0.33 mol) of 20 in 37 cm³ (0.5 mol) of thionylchloride was stirred at room temperature for 18 hours. Excess thionylchloride was removed at 10 mbar, and the oily residue was freed fromadhering residues of thionyl chloride by repeated dissolution in 100 cm³toluene in each case and stripping off in vacuo.

The acid chloride was taken up in 200 cm³ of toluene and added dropwiseat 10° C. to a suspension of 44 g (0.33 mol) of AlCl₃ in 1000 cm³ oftoluene, and the reaction mixture was heated at 80° C. for 3 hours,poured into 1000 g of ice and acidified to pH 1 by means of concentratedaqueous HCl. The organic phase was separated off, and the aqueous phasewas then extracted three times with 200 cm³ of methylene chloride ineach case. The combined organic phases were washed with saturatedaqueous NaCl₃ solution and saturated aqueous NaCl solution andsubsequently dried (MgSO₄). Chromatography on 1000 g of silica gel(hexane/methylene chloride) gave 12 g (13%) of 21.

¹ H-NMR (100 MHz, CDCl₃); 7.3-8.0 (m, 10H, arom. H), 2.2-3.2 (m, 3H, CH₂and CH), 1.2 (d, 3H, CH₃).

5. 2-Methyl-7-(1-naphthyl)indene (22)

1.3 g (33 mmol) of NaBH, were added at 0° C. to a solution of 12 g (44mmol) of 21 in 100 cm³ of THF/methanol 2:1, the reaction mixture wasstirred at room temperature for 18 hours and poured into 100 g of ice,concentrated aqueous HCl was added to pH 1, and the mixture wasextracted a number of times with Et₂ O. The combined organic phases werewashed with saturated aqueous NaHCO₃ solution and saturated aqueous NaClsolution and subsequently dried (MgSO₄).

The crude product was taken up in 200 cm³ of toluene, 0.5 g of p-toluenesulfonic acid was added, the reaction mixture was refluxed for 2 hourson a water separator and washed 3 times with 50 cm³ of saturated aqueousNaHCO, solution, and the solvent was removed in vacuo. Filtrationthrough 200 g of silica gel (hexane/methylene chloride) gave 10 g (86%)of 22 as a colorless oil.

¹ H-NMR (100 MHz, CDCl₃): 7.0-8.0 (m, 10H, arom. H), 6.6 (m, 1H, CH),3.0 (m, 2H, CH₂), 2.0 (m, 3H, CH₃).

6. Dimethylbis(2-methyl-4-(1-naphthyl)indenyl)silane (23)

14.4 cm³ (50 mmol) of a 20% strength solution of butyllithium in toluenewere added at room temperature to a solution of 10 g (38 mmol) of 22 in100 cm³ of H₂ O- and O₂ -free toluene and 5 ml of H₂ O- and O₂ -freeTHF, and the mixture was heated at 80° C. for 2 hours. The yellowsuspension was subsequently cooled to 80° C., and 2.5 g (19 mmol) ofdimethyldichlorosilane were added. The reaction mixture was heated at80° C. for a further 1 hour and subsequently washed with 50 cm³ of H₂ O.The solvent was removed in vacuo, and the residue was recrystallizedfrom heptane at -20° C., giving 8.2 g (75%) of 23 as colorless crystals.

¹ H-NMR (100 MHz, CDCl₃): 7.2-8.1 (m, 20H, arom. H), 6.4 (m, 2H,H--C(3)), 4.0 (m, 2H, H--C (1)), -0.1, (s, 6H, C₃ Si).

7. rac-Dimethylsilanediylbis (2-methyl-4-(1-naphthyl)indenyl)zirconiumdichloride (24)

10.5 cm³ of a 20% strength solution of butyllithium in toluene wereadded at room temperature under argon to a solution of 8.0 g (14 mmol)of 23 in 70 cm³ of H₂ O- and O₂ -free Et₂ O, and the mixture wassubsequently refluxed for 3 hours. The solvent was removed in vacuo, andthe residue was filtered through a G3 Schlenk frit with 50 ml of H₂ O-and O₂ -free hexane, then washed with 50 ml of H₂ O- and O₂ -free hexaneand dried (0.1 mbar, RT).

The dilithio salt was added at -78° C. to a suspension of 3.2 g (14mmol) of zirconium tetrachloride in 80 cm³ of methylene chloride, andthe mixture was warmed to room temperature over the course of 18 hourswith magnetic stirring. The batch was filtered through a G3 frit, andthe residue was then extracted in portions with a total of 400 cm³ ofmethylene chloride. The combined filtrates were freed from solvent invacuo and recrystallized from methylene chloride. 1.5 g (15%) of theracemic and meso forms in the ratio 1:1 were obtained. Furtherrecrystallization from methylene chloride gave the racemic complex inthe form of yellow crystals.

¹ -NMR (100 MHz, CDCl₃): 7.0-8.0 (m, 22H, arom. H), 6.5 (s, 2H, H--C(3)), 2.2 (s, 6H, CH₃), 1.3 (s, 6H, CH₃ Si). Mass spectrum: 729 M⁺, correctdecomposition pattern.

EXAMPLE Frac-Dimethylsilanediylbis(2-methyl-4-(2-naphthyl)indenyl)zirconiumDichloride (31) 1. 2-(2-Naphthyl)toluene (25)

14 g (0.57 mol) of magnesium turnings were covered by 150 ml of H₂P-free Et₂ O, and the Grignard reaction was initiated by means of 5 g of2-bromotoluene and a few grains of iodine. 95 g (0.58 mol) of1-bromotoluene in 450 ml of H₂ O-free Et₂ O were subsequently addeddropwise at such a rate that the reaction mixture was kept at the boil.When the addition was complete, boiling was continued until themagnesium had reacted fully.

The Grignard solution was subsequently added dropwise to a solution of120 g (0.57 mol) of 2-bromonaphthalene and 3.5 g ofbis(triphenylphosphine)nickel dichloride in 800 cm³ of toluene at such arate that the internal temperature did not exceed 50° C. The mixture wassubsequently refluxed for a further 3 hours, 500 ml of 10% strengthaqueous HCl were added, the phases were separated, and the organic phasewas freed from solvents in vacuo. Filtration through silica gel (hexane)gave 107 g (87%) of 25 as a colorless oil.

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.9 (m, 11H, arom. H), 1.9 (s, 3H, CH₃).

2. 2-(2-Naphthyl)benzyl bromide (26)

105 g (0.48 mol) of 25 and 90 g (0.5 mol) of N-bromosuccinimide weredissolved in 2000 cm³ of tetrachloromethane at room temperature, 3 g ofazobisisobutyronitrile were added, and the mixture was refluxed for 4hours. The succinimide which precipitated was filtered off, the solventwas removed in vacuo, and the residue was purified by filtration through1000 g of silica gel (hexane/methylene chloride 9:1), giving 112 g (79%)of 26 as a colorless lachrymatory oil.

¹ H-NMR (100 MHz, CDCl₃): 6.9-8.0 (m, 11H, arom. H), 4.1 (s, 2H, CH₂Br).

3. (±)-2-(2-(2-naphthyl)benzyl)propionic acid (27)

70 g (0.37 mmol) of diethyl methylmalonate dissolved in 50 cm³ of H₂O-free EtOH were added dropwise at room temperature to 8.5 g (0.37 mmol)of sodium in 100 cm³ of H₂ O-free EtOH. 110 g (0.37 mmol) of 26 in 200cm³ of H₂ O-free EtOH were subsequently added dropwise, and the mixturewas refluxed for 3 hours. 62 g (1.1 mol) of KOH dissolved in 100 cm³ ofH₂ O were added at room temperature, and the mixture was refluxed for afurther 4 hours. The solvent was removed in vacuo, H₂ O was added to theresidue until the latter had dissolved completely, and the mixture wasacidified to pH 1 by means of concentrated aqueous HCl. The precipitatewhich had formed was filtered off with suction, dried and heated at 130°C. for 1 hour, giving 90 g (84%) of 27 as a viscous oil.

¹ H-NMR (100 MHz, CDCl₃): 10.9 (s, 1H, COOH), 7.0-8.1 (m, 1H, arom. H)2.3-3.0 (m, 3H, CH₂ and CH), 1.0 (d, 3H, CH₃).

4. (±)-2-Methyl-4-(2-naphthyl)-1-indanone (28)

A solution of 89 g (0.31 mol) of 27 in 37 cm³ (0.5 mol) of thionylchloride was stirred at room temperature for 18 hours. Excess thionylchloride was removed at 10 mbar, and the oily residue was freed fromadhering residues of thionyl chloride by repeated dissolution in 100 cm³of toluene in each case and stripping off in vacuo.

The acid chloride was taken up in 200 cm³ of toluene and added dropwiseat 10° C. to a suspension of 44 g (0.33 mol) of AlCl₃ in 1000 cm³ oftoluene, and the reaction mixture was heated at 80° C. for 3 hours,poured into 1000 g of ice and acidified to pH 1 by means of concentratedaqueous HCl. The organic phase was separated off, and the aqueous phasewas then extracted three times with 200 cm³ of methylene chloride ineach case. The combined organic phases were washed with saturatedaqueous NaHCO₃ solution and saturated aqueous NaCl solution andsubsequently dried (MgSO₄). Chromatography on 1000 g of silica gel(hexane/AeOEt) gave 27 g (33%) of 28.

¹ H-NMR (100 MHz, CDCl₃): 7.1-8.0 (m, 10H, arom. H), 2.2-3.3 (m, 3H, CH₂and CH), 1.1 (d, 3H, CH₃).

5. 2-Methyl-7-2-naphthyl)indene (29)

3.8 g (100 mmol) of NaBH₄ were added at 0° C. to a solution of 27 g (100mmol) of 28 in 200 cm³ of THF/methanol 2:1, the reaction mixture wasstirred at room temperature for 18 hours and poured into 100 g of ice,concentrated aqueous HCl was added to pH 1, and the mixture wasextracted a number of times with Et₂ O. The combined organic phases werewashed with saturated aqueous NaHCO₃ solution and saturated aqueous NaClsolution and subsequently dried (MgSO₄).

The crude product was taken up in 500 cm³ of toluene, 1.5 g of p-toluenesulfonic acid was added, the reaction mixture was refluxed for 2 hourson a water separator and washed 3 times with 50 cm³ of saturated aqueousNaHCO₃ solution, and the solvent was removed in vacuo. Filtrationthrough 200 g of silica gel (hexane/methylene chloride) gave 18.4 g(72%) of 29 as a colorless oil.

¹ H-NMR (100 MHz, CDCl₃): 7.0-8.0 (m, 10H, arom. H), 6.6 (m, 1H, CH),3.0 (m, 2H, CH₂), 2.0 (m, 3H, CH₃).

6. Dimethylbis(2-methyl-4-(2-naphthyl)indenyl)silane (30)

26 cm³ (70 mmol) of a 20% strength solution of butyllithium in toluenewere added at room temperature to a solution of 18 g (70 mmol) of 29 in70 cm³ of H₂ O- and O₂ -free toluene and 4 ml of H₂ O- and O₂ -free THF,and the mixture was heated at 80° C. for 2 hours. The yellow suspensionwas subsequently cooled to 0° C., and 4.5 g (35 mmol) ofdimethyldichlorosilane were added. The reaction mixture was heated at80° C. for a further 1 hour and subsequently washed with 50 cm³ of H₂ O.The solvent was removed in vacuo, and the residue was recrystallizedfrom heptane at -20° C., giving 10.8 g (54%) of 30 as colorlesscrystals.

¹ NMR (100 MHz, CDCl₃): 7.0-8.1 (m, 20H, arom. H), 6.4 (m, 2H, H--C(3)),4.0 (m, 2H, H--C (1)), -0.1, (s, 6H, CH₃ Si).

7. rac-Dimethylsilanediylbis (2-methyl-4-(2-naphthyl)indenyl)zirconiumDichloride (31)

13.6 cm³ of a 20% strength solution of butyllithium in toluene wereadded at room temperature under argon to a solution of 10.5 g (18 mmol)of 30 in 70 cm³ of H₂ O- and O₂ -free Et₂ O, and the mixture wassubsequently refluxed for 3 hours. The solvent was removed in vacuo, andthe residue was filtered through a G3 Schlenk frit with 50 ml of H₂ O-and O₂ -free hexane, then washed with 50 ml of H₂ O- and O₂ -free hexaneand dried (0.1 mbar, RT).

The dilithio salt was added at -78° C. to a suspension of 4.2 g (18mmol) of zirconium tetrachloride in 80 cm³ of methylene chloride, andthe mixture was warmed to room temperature over the course of 18 hourswith magnetic stirring. The batch was filtered through a G3 frit, andthe residue was then extracted in portions with a total of 400 cm³ ofmethylene chloride. The combined filtrates were freed from solvent invacuo and recrystallized from methylene chloride. 3.1 g (23%) of theracemic and meso forms in the ratio 1:1 were obtained. Furtherrecrystallization from methylene chloride gave the racemic complex inthe form of yellow crystals.

¹ H-NMR (100 MHz, CDCl₃): 7.0-8.0 (m, 22H, arom. H), 6.9 (s, 2H,H--C(3)), 2.2 (S, 6H, CH₃), 1.3 (s, 6H, CH₃ Si). Mass spectrum: 729 M⁺,correct decomposition pattern.

EXAMPLE G rac-Ethanediylbis(2-methyl-4-phenylindenyl)zirconiumDichloride (33) 1. 1,2-Bis(2-methyl-4-phenylindenyl)ethane (32)

90 cm³ (0.24 mol) of a 20% strength solution of butyllithium in toluenewere added at room temperature under argon to a solution of 50 g (0.24mol) of 3 in 500 ml of THF. The mixture was stirred at 60° C. for 2hours, and cooled to -78° C., 22.5 g (0.12 mol) of dibromoethane wereadded, and the mixture was warmed to room temperature over the course of18 hours. The reaction mixture was washed with 50 cm³ of H₂ O, thesolvent was removed in vacuo, and the residue was chromatographed on 500g of silica gel (hexane/methylene chloride 9:1), giving 2.5 g (5%) of 32as a yellow oil which solidified slowly at -20° C.

¹ H-NMR (100 MHz, CDCl₃): 7.0-8.1 (m, 20H, arom. H), 6.4 (m, 2H,H--C(3)), 4.0 (m, 2H, H--C (1)), -0.1, (s, 6H, CH₃ Si).

2. rac-Ethanediylbis(2-methyl-4-phenylindenyl)zirconium Dichloride (33)

4 cm³ (10 mmol) of a 20% strength solution of butyllithium in toluenewere added at room temperature under argon to a solution of 2.3 g (5mmol) of 32 in 20 ml of H₂ O- and O₂ -free Et₂ O, and the mixture wasrefluxed for 3 hours. The solvent was removed in vacuo, the residue wasfiltered through a G3 Schlenk frit with 30 ml of H₂ O- and O₂ -freehexane, then washed with 30 ml of H₂ O- and O₂ -free hexane and dried(0.1 mbar, RT).

The dilithio salt was added at -78° C. to a suspension of 1.2 g (5 mmol)of zirconium tetrachloride in 30 cm³ of methylene chloride, and themixture was warmed to a temperature over the course of 18 hours withmagnetic stirring. The batch was filtered through a G3 frit, and theresidue was then extracted in portions with a total of 100 cm³ ofmethylene chloride. The combined filtrates were freed from solvent invacuo and recrystallized from methylene chloride/hexane. 0.5 g (18%) ofthe racemic and meso forms in the ratio 1:1 was obtained. Furtherrecrystallization from toluene gave the racemic complex in the form ofyellow crystals.

¹ H-NMR (100 MHz, CDCl₃): 7.0-7.7 (m, 16H, arom. H), 6.6 (m, 2H,H--C(3)), 3.4-4.1 (m, 4H, H₂ C-CH₂), 2.1 (s, 6H, CH₃). Mass spectrum :598 M⁺, correct decomposition pattern.

EXAMPLE H Me₂ Si(2-Me-4-Ph-indenyl)₂ ZrMe[BPh₄ ] (35) 1.rac-Dimethylsilanediylbis(2-Methyl-4-phenylindenyl)dimethylzirconium(34)

1 cm³ of a 1.6 M (1.6 mmol) solution of methyllithium in Et₂ O wereadded at -30° C. to 0.5 g (0.8 mmol) of rac-5 in 10 cm³ of H₂ O and O₂-free Et₂ O, and the mixture was stirred at 0° C. for 1 hour. Thesolvent was subsequently removed in vacuo, and the residue was taken upin 20 cm³ of H₂ O- and O₂ -free hexane and filtered off through a G3frit, giving 0.34 g (72%) of 34. Mass spectrum: 588 M⁺, correctdecomposition pattern.

2. Me₂ Si(2-Me-4-Ph-Indenyl)₂ ZrMe[BPh₄ ] (35)

0.2 g (0.3 mmol) of 34 were added at 0° C. to 0.25 g (mmol) oftributylammonium tetraphenylborate in 30 cm³ of toluene. The mixture waswarmed to 50° C. with stirring and stirred at this temperature for 15minutes. An aliquot portion of the solution was used for thepolymerization.

EXAMPLE 1

A dry 16 dm³ reactor was first flushed with nitrogen and subsequentlywith propylene and filled with 10 dm³ of liquid propylene. 30 cm³ of atoluene solution of methylaluminoxane were then added, and the batch wasstirred at 30° C. for 15 minutes.

In parallel, 1.1 mg of rac-5 were dissolved in 20 cm³ of a toluenesolution of methylaluminoxane (27 mmol of Al) and reacted by standingfor 15 minutes. The solution was then introduced into the reactor andheated to the polymerization temperature of 50° C. (4° C./min) by supplyof heat, and the polymerization system was kept at 50° C. for 1 hour bycooling. The polymerization was terminated by addition of 20 cm³ ofisopropanol. The excess monomer was removed in gas form, and the polymerwas dried in vacuo, giving 0.9 kg of polypropylene. The reactorexhibited thin deposits on the internal wall and stirrer. The catalystactivity was 818 kg of PP/g of metallocene×h. VI=905 cm³ /g; m.p.=159.4°C.; II=98.8%; mmmm=95.4%; M_(w) =1,100,000 g/mol; M_(w) /M_(n) =2.5.

EXAMPLE 2

The polymerization of Example 1 was repeated with the difference thatthe catalyst used was 0.9 mg of rac-5 and the polymerization temperaturewas 70° C. 1.4 kg of polypropylene were obtained. The reactor exhibitedthick deposits on the internal wall and stirrer. Catalyst activity was1,555 kg of PP/g of metallocene×h. VI=719 cm³ /g; m.p.=157.7° C.

EXAMPLE 3

22 cm³ of the suspension of "MAO on SiO₂ " (49 mmol of Al) wasintroduced under argon into a G3 Schlenk frit, and a solution of 4.5 mgof rac-5 in 10 cm³ of toluene (7.2 μmol of Zr) was added. The reactionmixture was stirred at room temperature for 30 minutes, with aspontaneous color change to red gradually fading. The mixture wassubsequently filtered, and the solid was washed 3 times with 10 cm³ ofhexane. The hexane-moist filter residue which remained was resuspendedin 20 cm³ of hexane for the polymerization.

In parallel, a dry 16 dm³ reactor was flushed first with nitrogen andsubsequently with propylene and filled with 10 dm³ of liquid propylene.3 cm³ of triisobutylaluminum (pure, 12 mmol) were then diluted with 30cm³ of hexane and introduced into the reactor and the batch was stirredat 30° C. for 15 minutes. A catalyst suspension was subsequentlyintroduced into the reactor and heated to the polymerization temperatureof 50° C. (4° C./min), and the polymerization system was kept at 50° C.for 1 hour by cooling. Polymerization was terminated by addition of 20cm³ of isopropanol. The excess monomer was removed in gas form, and thepolymer was dried in vacuo. 300 g of polypropylene powder were obtained.The reactor exhibited no deposits on the internal wall or stirrer. Thecatalyst activity was 67 kg of PP/g of metallocene×h. VI=1380 cm³ /g;m.p.=156° C.

EXAMPLE 4

The synthesis of the supported catalyst system from Example 3 wasrepeated with the difference that 13 cm³ (29 mmol of Al) of thesuspension "MAO on SiO₂ " and 1.8 mg of rac-5 (2.9 μmol of Zr) wereused.

The polymerization was carried out analogously to Example 3 at 70° C.420 g of polypropylene powder were obtained. The reactor exhibited nodeposits on the internal wall or stirrer. The catalyst activity was 233kg of PP/g of metallocene×h. VI=787 cm³ /g; m.p.=149.5° C.

EXAMPLE 5

The synthesis of the supported catalyst system from Example 3 wasrepeated with the difference that 150 cm³ (335 mmol of Al) of thesuspension "MAO on SiO₂ " and 44.2 mg of rac-5 (70.3 μmol of Zr) wereused and the reaction mixture was stirred at room temperature for 60minutes. The solid was subsequently filtered off and washed 3 times with50 cm³ of hexane. The hexane-moist filter residue which remained wasdried in vacuo to give a free-flowing, pale pink powder. 33.3 g ofsupported, dry catalyst were obtained.

For the polymerization, 2.98 g of this dry catalyst (4 mg=6.3 μmol ofZr) were resuspended in 20 cm³ of hexane.

The polymerization was carried out analogously to Example 3 at 70° C.1.05 kg of polypropylene powder were obtained. The reactor exhibited nodeposits on the internal wall or stirrer. The catalyst activity was 263kg of PP/g of metallocene×h. VI=944 cm³ /g; m.p.=156° C.

EXAMPLE 6

A dry 1.5 dm³ reactor was flushed with N₂ and filled at 20° C. with 750cm³ of a benzine cut with the boiling range 100-120° C. from which thearomatic compounds had been removed ("®Exxsol 100/120"). The gas spaceof the reactor was then flushed free of nitrogen by injecting 8 bar ofpropylene and releasing the pressure, and repeating this procedure fourtimes. 3.75 cm³ of a toluene solution of methylaluminoxane (10% byweight of MAO) were then added. The reactor contents were then heated to30° C. over the course of 15 minutes with stirring, and the overallpressure was set at 8 bar by addition of propylene at a stirring rate of500 rpm.

In parallel, 0.1 mg of rac-5 were dissolved in 1.25 cm³ of a toluenesolution of methylaluminoxane and reacted fully by standing for 15minutes. The solution was then introduced into the reactor, and thepolymerization system was heated to a temperature of 50° C. and kept atthis temperature for 1 hour by appropriate cooling. The pressure waskept at 8 bar during this time by appropriate supply of propylene, thereaction was then terminated by addition of 2 cm³ of isopropanol, andthe polymer was filtered off and dried in vacuo.

16 g of polypropylene were obtained. The reactor exhibited deposits onthe internal wall and stirrer. The catalyst activity (CTY_(red)) was 20kg of PP/g of metallocene×h×bar. VI=833 cm³ /g; m.p.=159° C.

EXAMPLE 7

The polymerization of Example 6 was repeated with the difference thatthe polymerization temperature was 60° C.

35 g of polypropylene were obtained. The reactor exhibited deposits onthe internal wall and stirrer. The catalyst activity (CTY_(red)) was 44kg of PP/g of metallocene×h×bar. VI=484 cm³ /g; m.p.=159° C.

EXAMPLE 8

The polymerization from Example 6 was repeated with the difference thatthe polymerization temperature was 70° C.

88 g of polypropylene were obtained. The reactor exhibited deposits onthe internal wall and stirrer. The catalyst activity (CTY_(red)) was 110kg of PP/g of metallocene×h×bar. VI=414 cm³ /g; m.p.=159° C.

EXAMPLES 9-12

The procedure was as in Example 2. However, hydrogen was metered inbefore the filling with liquid propylene:

    ______________________________________                                                Dm.sup.2 (s.t.)                                                                           Metallocene activity                                                                         VI                                           Example of H.sub.2 [kg of PP/g of Met × h] [cm.sup.3 /g]              ______________________________________                                         9      1.5         1640           495                                          10  3 1590 212                                                                11 4.5 1720 142                                                               12 200 1580  17                                                             ______________________________________                                    

Examples 9-12 demonstrate the good hydrogen utilization of themetallocene according to the invention. Molecular weight regulation intothe wax region (see Example 12) is possible.

EXAMPLE 13

The procedure was as in Example 3. However, 0.2 bar of hydrogen wasinjected into the reactor before addition of the catalyst, and thepolymerization temperature was 60° C. However, ethylene was metered inat a uniform rate during the polymerization. In total. 12 g of ethylenewere introduced into the reactor. 0.4 kg of ethylene-copolymer wereobtained. The metallocene activity was 88 kg of copolymer/g ofmetallocene×h. The ethylene content of the polymer was 2.4% by weight,and the ethylene was predominantly incorporated as isolated units.VI=200 cm³ /g; melting point 143° C.

EXAMPLE 14

The procedure was as in Example 13. However, a total of 34 g of ethylenewere metered in during polymerization. 0.38 kg of ethylene-propylenecopolymer containing 7% by weight of ethylene was obtained. VI=120 cm³ ;melting point 121° C.

EXAMPLE 15

The procedure was as in Example 4. However, 4 g of ethylene were meteredin during the polymerization and 0.1 bar of hydrogen was injected beforethe polymerization. 0.52 kg of ethylene-propylene copolymer wereobtained. The metallocene activity was 286 kg of copolymer/g ofmetallocene×h. The ethylene content of the polymer was 6.1% by weight,and the majority of the ethylene was incorporated as isolated units.VI=150 cm³ /g; melting point 116° C.

EXAMPLE 16

A dry 150 dm³ reactor was flushed with nitrogen and filled at 20° C.with 80 dm³ of a benzine cut having the boiling range of 100-120° C.from which the aromatic compounds had been removed. The gas space wasthen flushed free of nitrogen by injecting 2 bar of propylene andreleasing the pressure, and repeating this procedure four times. After50 l of liquid propylene had been added, 64 cm³ of a toluene solution ofmethylaluminoxane (corresponding to 100 mmol of Al, molecular weight1080 g/mol according to cryoscopic determination) were added, and thereactor contents were heated to 50° C. A hydrogen content of 2.0% wasestablished in the gas space of the reactor by metering in hydrogen andwas later kept constant during the 1st polymerization step by subsequentmetering in.

9.8 mg of rac-7 were dissolved in 32 ml of the toluene solution ofmethylaluminoxane (corresponding to 50 mmol of Al) and were introducedinto the reactor after 15 minutes. The polymerization was then carriedout in a 1st polymerization step for 5 hours at 50° C. The gaseouscomponents were then removed at a reactor pressure of 3 bar, and 2000 gof ethylene gas were fed in. The reactor pressure increased to 8 barduring this operation, and the polymerization was continued for afurther 14 hours at 40° C. before the reaction was terminated by meansof CO₂ gas.

18.6 kg of block copolymer were obtained, corresponding to a metalloceneactivity of 99.9 kg of copolymer/g of metallocene×h. VI=230 cm² /g; MFI(230/5)=11 dg/min, MFI (230/2.16)=3.7 dg/min; melting point of thepolymer in the 1st polymerization step: 159° C., glass transitiontemperature of the polymer in the 2nd polymerization step: -38° C. Theblock copolymer contained 5% of ethylene. Fractionation of the productgave the following composition: 69% by weight of homopolymer, 31% byweight of copolymer, the copolymer having an ethylene content of 15% byweight, and the mean C₂ block length was 2.2.

EXAMPLE 16a

The procedure was as in Example 16.

3 mg of rac-24 were dissolved in 32 ml of the toluene solution ofmethylaluminoxane (corresponding to 50 mmol of Al) and were introducedinto the reactor after 15 minutes. The polymerization was then carriedout in a 1st polymerization step for 2.5 hours at 50° C. The gaseouscomponents were then removed at a reactor pressure of 3 bar, and 3000 gof ethylene gas were fed in. The reactor pressure increased to 8 barduring this operation, and the polymerization was continued for afurther 8 hours at 40° C. before the reaction was terminated by means ofCO₂ gas.

16.5 kg of block copolymer were obtained, corresponding to a metalloceneactivity of 524 kg of copolymer/g of metallocene×h. VI=480 cm³ /g; MFI(230/5)=2 dg/min, melting point of the polymer in the 1st polymerizationstep: 162° C., glass transition temperature of the polymer in the 2ndpolymerization step: -54° C. The block copolymer contained 15% ofethylene.

EXAMPLE 17

The procedure was as in Example 1, but 12.5 mg of metallocene rac-7 wereused. 1.5 kg of polypropylene were obtained; the metallocene activitywas 120 kg of PP/g of metallocene×h. VI=1050 cm³ /g; melting point 159°C.

EXAMPLE 18

The procedure was as in Example 2, but 4.1 mg of metallocene rac-7 wereused. 1.3 kg of polypropylene were obtained; the metallocene activitywas 317 kg of PP/g of metallocene×h. VI=555 cm³ /g; melting point 157°C.

COMPARATIVE EXAMPLE A

The procedure was as in Example 1, but 12.5 mg ofrac-phenyl(methyl)silanediylbis(2-methyl-1-indenyl)zirconium dichloridewere used. 1.35 kg of polypropylene were obtained; the metalloceneactivity was 108 kg of PP/g of metallocene×h. VI=1050 cm³ /gl; meltingpoint 149° C.

COMPARATIVE EXAMPLE B

The procedure was as in Example 1, but 12.5 mg of rac-phenyl (methyl)silanediylbis (1-indenyl) zirconium dichloride were used. 0.28 kg ofpolypropylene were obtained; the metallocene activity was 22.4 kg ofPP/g of metallocene×h. VI=74 cm³ /gl; melting point 141° C.

EXAMPLE 19

The procedure was as in Example 1, but 3.3 mg of 24 were used. 0.78 kgof polypropylene were obtained; metallocene activity was 237 kg of PP/gof metallocene×h. VI=1700 cm³ /g; melting point 163° C., M_(w) =2.1×10⁶g/mol, MFI 230/21.6=1 dg/min; M_(w) /M_(n) =2.1.

EXAMPLE 19a

The procedure was as in Example 2, but 1.0 mg of rac-24 were used. 1.2kg of polypropylene were obtained. The metallocene activity was 1200 kgof PP/g of metallocene×h. VI=1100 cm³ /g. Melting point=161° C.

EXAMPLE 20

The procedure was as in Example 1; however the polymerizationtemperature was 40° C. 6.0 mg of 17 were used. 1.95 kg of polypropylenewere obtained; the metallocene activity was 325 kg of PP/g ofmetallocene×h. VI=1320 cm³ /g; melting point 162° C., M_(w) =1.79×10⁶g/mol, M_(w/) /M_(n) =2.3.

COMPARATIVE EXAMPLE C

The procedure was as in Example 20, but the conventional metallocenerac-dimethylsilanediylbis(2-ethyl-1-indenyl)zirconium dichloride wasused. 0.374 kg of polypropylene were obtained; the metallocene activitywas 62.3 kg of PP/g of metallocene×h. VI=398 cm³ /g; melting point 147°C., M_(w) =450,000 g/mol, M_(w) /M_(n) =2.5.

EXAMPLE 21

The procedure was as in Example 1, but 5.2 mg of 31 were used. 1.67 kgof polypropylene were obtained; the metallocene activity was 321 kg ofPP/g of metallocene×h. VI=980 cm³ /g; melting point 158° C.

EXAMPLE 22

The procedure was as in Example 11 but the polymerization was carriedout at 30° C. and 3.7 mg of 33 were used. 0.35 kg of polypropylene wereobtained; the metallocene activity was 94 kg of PP/g of metallocene×h.VI=440 cm³ /g; melting point 153° C.

EXAMPLE 23

A dry 16 dm³ reactor was flushed with propylene and filled with 10 dm³of liquid propylene. 1.1 cm³ of the reaction product from H.2(corresponding to 7.5 mg of 34) were then dissolved in 20 cm³ of tolueneand introduced into the reactor at 30° C. The reactor was heated to 50°C. (10° C./min) and the polymerization system was kept at thistemperature for 1 hour by cooling. The polymerization was terminated byaddition of CO₂ gas. The excess monomer was removed in gas form, and thepolymer was dried in vacuo at 80° C. 2.45 kg of polypropylene wereobtained. VI=875 cm³ /g; melting point 160° C.

EXAMPLE 24

A dry 16 dm³ reactor was flushed with nitrogen and filled at 20° C. with10 dm³ of a benzine cut having the boiling range 100-120° C. from whichthe aromatic compounds had been removed. The gas space of the reactorwas then flushed free of nitrogen by injecting 2 bar of ethylene andreleasing the pressure and repeating this operation 4 times. 30 cm³ of atoluene solution of methylaluminoxane (corresponding to 45 mmol of Al,molecular weight 700 g/mol according to cryoscopic determination) werethen added. The reactor contents were heated to 30° C. over the courseof 15 minutes with stirring, and the overall pressure was set at 5 barby addition of ethylene at a stirring rate of 250 rpm.

In parallel, 3.2 g of 12 were dissolved in 20 cm³ of a toluene solutionof methylaluminoxane and were preactivated by standing for 15 minutes.The solution was then introduced into the reactor, and thepolymerization system was heated to a temperature of 50° C. and kept atthis temperature for 4 hours by appropriate cooling. The overallpressure was kept at 5 bar during this time by a appropriate supply ofethylene.

The polymerization was terminated by addition of 20 ml of isopropanol,and the polymer was filtered off and dried in vacuo. 0.7 kg ofpolyethylene were obtained. VI=690 cm³ /g.

EXAMPLE 25

The procedure of Example 24 was followed. In contrast to Example 23, 1.8mg of rac-7 were employed, and the polymerization system was heated to70° C. and kept at this temperature for 1 hour. 0.9 kg of polyethylenewere obtained. VI=730 cm³ /g.

EXAMPLE 26

15 g of "F-MAO on SiO₂ " (111 mmol of Al) were suspended in 100 cm³ oftoluene in a stirrable vessel and cooled to -20° C. At the same time,155 mg (0.246 mmol) of rac-5 were dissolved in 75 cm³ of toluene andadded dropwise to this suspension over the course of 30 minutes. Themixture was slowly warmed to room temperature with stirring, thesuspension taking on a red color. The mixture was subsequently stirredat 80° C. for 1 hour, cooled to room temperature and filtered, and thesolid was washed 3 times with 100 cm³ of toluene in each case and oncewith 100 cm³ of hexane. The filtrate was red. The hexane-moist filterresidue which remained was dried in vacuo, giving 13.2 g offree-flowing, pale red, supported catalyst. Analysis gave a content of3.2 mg of zirconocene per gram of catalyst.

Polymerization: For the polymerization, 2.08 g of the catalyst weresuspended in 50 cm³ of a benzine cut having the boiling range of100-120° C. from which the aromatic compounds had been removed. Thepolymerization was carried out analogously to Example 3 at 60° C. 1100 gof polypropylene powder were obtained. The reactor exhibited no depositson the internal wall or stirrer. Activity=165 kg of PP/(g ofmetallocene×h). VI=1100 cm³ /g. Melting point=153° C.; M_(w) =1,485,000;M_(w) /M_(n) =3.2; MFI 230/5=0.1 dg/min; BD=440 g/dm³.

EXAMPLE 27

1.31 g of the catalyst from Example 26 were suspended in 50 cm³ of abenzine cut having the boiling range of 100-120° C. from which thearomatic compounds had been removed. The polymerization was carried outanalogously to Example 3 at 70° C. 1300 g of polypropylene powder wereobtained. The reactor exhibited no deposits on the internal wall orstirrer. Activity=310 kg of PP/(g of metallocene×h). VI=892 cm³ /g;melting point=150° C., M_(w) =1,290,000; M_(w) /M_(n) =3.0; BD=410g/dm³.

EXAMPLE 28

The supporting procedure from Example 26 was repeated with thedifference that 0.845 g of rac-5 dissolved in 500 cm³ of toluene werereacted with 90 g of "F-MAO on SiO₂ " and suspended in 500 cm³ oftoluene. 84 g of red, pulverulent catalyst were obtained. Analysis gavea content of 9 mg of metallocene per gram of solid, and the red filtratecontained 13 mg of zirconium.

Polymerization: 1.1 g of the supported catalyst were suspended in 50 mlof a benzine cut having a boiling range of 100-120° C. from which thearomatic compounds had been removed. The polymerization was carried outanalogously to Example 3 at 70° C. 2850 g of polypropylene powder wereobtained. The reactor exhibited no deposits on the internal wall orstirrer. Activity=288 kg of PP/(g of metallocene×h); VI=638 cm³ /g;melting point=150° C; MFI 230/5=0.5 dg/min; BD=410 g/dm³.

EXAMPLE 29

A microporous polypropylene powder (AKZO) having a particle size ofsmaller than 100 μm was freed from impurities by extraction with toluenein a Soxhlet extractor under inert conditions and subsequently washedwith 20% strength by weight of trimethylaluminum solution in toluene anddried in vacuo. In parallel, 51.1 mg of rac-5 were dissolved in 40 cm³of a toluene solution of methylaluminoxane and reacted fully by standingfor 15 minutes. 16.5 g of the PP powder were metered in, and the gas inthe pores of the support and some of the solvent were removed by brieflyapplying a vacuum, and the catalyst solution was absorbed fully.Vigorous shaking of the reaction vessel gave 46 g of homogeneous, finelydivided and free-flowing red powder. 10 g of the supported catalystpowder were prepolymerized for 30 minutes with ethylene under inertconditions in a rotary evaporator. The ethylene excess pressure was keptconstant at 0.1 bar by means of a pressure-regulation valve, and themixing of the catalyst powder was achieved by continuous rotation of thereaction vessel with cooling at 0° C. 12 g of prepolymerized catalystwere obtained.

Polymerization: 4.6 g of the supported, prepolymerized catalyst weresuspended in 50 cm³ of a benzine cut having the boiling range 100-120°C. from which the aromatic compounds had been removed. Polymerizationwas carried out analogously to Example 3 at 70° C. 250 g ofpolypropylene powder were obtained. The reactor exhibited no deposits onthe internal wall or stirrer, and the mean particle size was 1,000 μm.Activity=59 kg of PP/(g of metallocene×h); VI=734 cm³ /g. Meltingpoint=152° C.; BD=390 g/dm³.

EXAMPLE 30

1 g of the supported, non-prepolymerized catalyst from Example 29 wassuspended in 50 cm³ of n-decane for the polymerization. Thepolymerization was carried out analogously to Example 3 at 70° C. 600 gof polypropylene were obtained. The reactor exhibited thin deposits onthe internal wall and stirrer, and the mean particle diameter was >2000μm. Activity=540 kg of PP/(g of metallocene×h); VI=1400 cm³ /g; meltingpoint=157.7° C.; BD=280 g/dm³.

What is claimed is:
 1. A compound of formula I ##STR11## in which M¹ isa metal from group IVb, Vb or VIb of the Periodic Table,R¹ and R² areidentical or different and are a hydrogen atom, a C₁ -C₁₀ -alkyl group,a C₁ -C₁₀ -alkoxy group, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -aryloxygroup, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀-alkylaryl group or a C₈ -C₄₀ -arylalkenyl group or an OH group, theradicals R³ are identical or different and are a hydrogen atom, ahalogen atom, a C₁ -C₁₀ -alkyl group, which may be halogenated, a C₆-C₁₀ -aryl group, an --NR¹⁶ ₂, --SR¹⁶, --OSiR¹⁶ ₃, --SiR¹⁶ ₃ or PR¹⁶ ₂radical, in which R¹⁶ is a halogen atom, a C₁ -C₁₀ -alkyl group or a C₆-C₁₀ -aryl group, R⁴ to R¹² are identical or different and are asdefined for R³, or adjacent radicals R⁴ to R¹², together with the atomsconnecting them, form one or more aromatic or aliphatic rings, or theradicals R⁵ and R⁸ or R¹², together with the atoms connecting them, forman aromatic or aliphatic ring, ##STR12## ═BR¹⁴, ═AlR¹⁴, --Ge--, --O--,--S--, ═SO, ═SO₂, ═NR¹⁴, ═CO, ═PR¹⁴ or ═P(O) R¹⁴, where R¹⁴ and R¹⁵ areidentical or different and are a hydrogen atom, a halogen atom, a C₁-C₁₀ -alkyl group, a C₁ -C₁₀ -fluoroalkyl group, a C₁ -C₁₀ -alkoxygroup, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -fluoroaryl group, a C₆ -C₁₀-aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀ -arylalkenyl group, or R¹⁴ andR¹⁵, in each case together with atoms connecting them, form one or morerings, and M² is silicon, germanium or tin.
 2. A compound of formula I##STR13## in which M¹ is a metal from group IVb, Vb or VIb of thePeriodic Table,R¹ and R² are identical or different and are a hydrogenatom, a C₁ -C₁₀ -alkyl group, a C₁ -C₁₀ -alkoxy group, a C₆ -C₁₀ -arylgroup, a C₆ -C₁₀ -aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀-arylalkyl group, a C₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀ -arylalkenylgroup or an OH group or a halogen atom, the radicals R³ are identical ordifferent and are a hydrogen atom, a halogen atom, a C₁ -C₁₀ -alkylgroup, which may be halogenated, a C₆ -C₁₀ -aryl group, an --NR¹⁶ ₂,--SR¹⁶, --OSiR¹⁶ ₃, --SiR¹⁶ ₃ or PR¹⁶ ₂ radical, in which R¹⁶ is ahalogen atom, a C₁ -C₁₀ -alkyl group or a C₆ -C₁₀ -aryl group, R⁴ to R¹²are identical or different and are as defined for R³, or adjacentradicals R⁴ to R¹², together with the atoms connecting them, form one ormore aromatic or aliphatic rings, or the radicals R⁵ and R⁸ or R¹²,together with the atoms connecting them, form an aromatic or aliphaticring, ##STR14## ═BR¹⁴, ═AlR¹⁴, --Ge--, --O--, --S--, ═SO, ═SO₂, ═NR¹⁴,═CO, ═PR¹⁴ or ═P(O) R¹⁴, where R¹⁴ is a hydrogen atom, a halogen atom, aC₁ -C₁₀ -alkyl group, a C₁ -C₁₀ -fluoroalkyl group, a C₁ -C₁₀ -alkoxygroup, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -fluoroaryl group, a C₆ -C₁₀-aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀ -arylalkenyl group, R¹⁵ is ahydrogen atom, halogen atom, a C₄ -C₁₀ -alkyl group, a C₁ -C₁₀-fluoroalkyl group, a C₁ -C₁₀ -alkoxy group, a C₆ -C₁₆ -aryl group, a C₆-C₁₀ -fluoroaryl group, a C₆ -C₁₀ -aryloxy group, a C₂ -C₁₀ -alkenylgroup, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀ -alkylaryl group or a C₈-C₄₀ -arylalkenyl group, or R¹⁴ and R¹⁵, in each case together withatoms connecting them, form one or more rings, and M² is silicon,germanium or tin.
 3. A compound of formula I, ##STR15## in which M¹ is ametal from group IVb, Vb or VIb of the Periodic Table,R¹ and R² areidentical or different and are a hydrogen atom, a C₁ -C₁₀ -alkyl group,a C₁ -C₁₀ -alkoxy group, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -aryloxygroup, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀-alkylaryl group or a C₈ -C₄₀ -arylalkenyl group or an OH group or ahalogen atom, the radicals R³ are identical or different and are ahydrogen atom, a halogen atom, a C₁ -C₁₀ -alkyl group, which may behalogenated, a C₆ -C₁₀ -aryl group, an --NR¹⁶ ₂, --SR¹⁶, --OSiR¹⁶ ₃,--SiR¹⁶ ₃ or PR¹⁶ ₂ radical, in which R¹⁶ is a halogen atom, a C₁ -C₁₀-alkyl group or a C₆ -C₁₀ -aryl group, R⁴ to R¹² are identical ordifferent and are as defined for R³, or adjacent radicals R⁴ to R¹²,together with the atoms connecting them, form one or more aromatic oraliphatic rings, or the radicals R⁵ and R⁸ or R¹², together with theatoms connecting them, form an aromatic or aliphatic ring, ##STR16##═BR¹⁴, ═AlR¹⁴, --Ge--, --O--, --S--, ═SO, ═SO₂, ═NR¹⁴, ═CO, ═PR¹⁴ or═P(O) R¹⁴, where R¹⁴ and R¹⁵ are different and are a hydrogen atom, ahalogen atom, a C₁ -C₁₀ -alkyl group, a C₁ -C₁₀ -fluoroalkyl group, a C₁-C₁₀ -alkoxy group, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -fluoroaryl group,a C₆ -C₁₀ -aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkylgroup, a C₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀ -arylalkenyl group, orR¹⁴ and R¹⁵, in each case together with atoms connecting them, form oneor more rings, and M² is silicon, germanium or tin.
 4. A compound offormula I, ##STR17## in which M¹ is a metal from group IVb, Vb or VIb ofthe Periodic Table,R¹ and R² are identical or different and are ahydrogen atom, a C₁ -C₁₀ -alkyl group, a C₁ -C₁₀ -alkoxy group, a C₆-C₁₀ -aryl group, a C₆ -C₁₀ -aryloxy group, a C₂ -C₁₀ -alkenyl group, aC₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀-arylalkenyl group, an OH group or a halogen atom, the radicals R³ areidentical or different and are a hydrogen atom, a halogen atom, a C₁-C₁₀ -alkyl group, which may be halogenated, a C₆ -C₁₀ -aryl group, a C₆-C₁₀ -aryl group, an --NR¹⁶ ₂, --SR¹⁶, --OSiR¹⁶ ₃, --SiR¹⁶ ₃ or PR¹⁶ ₂radical, in which R¹⁶ is a halogen atom, a C₁ -C₁₀ -alkyl group or a C₆-C₁₀ -aryl group, R⁴ to R¹² are identical or different and are asdefined for R³, or adjacent radicals R⁴ to R¹², together with the atomsconnecting them, form one or more aromatic or aliphatic rings, or theradicals R⁵ and R⁸ or R¹², together with the atoms connecting them, forman aromatic or aliphatic ring, ##STR18## ═BR¹⁴, ═AlR¹⁴, --Ge--, --O--,--S--, ═SO, ═SO₂, ═NR¹⁴, ═CO, ═PR¹⁴ or ═P(O) R¹⁴, where R¹⁴ and R¹⁵ areidentical or different and are a hydrogen atom, a halogen atom, a C₁-C₁₀ -alkyl group, a C₁ -C₁₀ -fluoroalkyl group, a C₁ -C₁₀ -alkoxygroup, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -fluoroaryl group, a C₆ -C₁₀-aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀ -arylalkenyl group, or R¹⁴ andR¹⁵, in each case together with atoms connecting them, form one or morerings, and M² is germanium or tin.
 5. A compound of formula I ##STR19##in which M¹ is Zr, Hf, or a metal from group, Vb or VIb of the PeriodicTable,R¹ and R² are identical or different and are a hydrogen atom, a C₁-C₁₀ -alkyl group, a C₁ -C₁₀ -alkoxy group a C₆ -C₁₀ -aryl group, a C₆-C₁₀ -aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkylgroup, a C₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀ -arylalkenyl group, an OHgroup or a halogen atom, the radicals R³ are identical or different andare a hydrogen atom, a halogen atom, a C₁ -C₁₀ -alkyl group which ishalogenated, C₁ -alkyl, a C₆ -C₁₀ -aryl group, an --NR¹⁶ ₂, --SR¹⁶,--OSiR¹⁶ ₃, --SiR¹⁶ ₃ or PR¹⁶ ₂ radical, in which R¹⁶ is a halogen atom,a C₁ -C₁₀ -alkyl group or a C₆ -C₁₀ -aryl group, R⁴ to R¹² are identicalor different and are a hydrogen atom, a halogen atom, a C₁ -C₁₀ -alkylgroup, which may be halogenated, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -arylgroup, an --NR¹⁶ ₂, --SR¹⁶, --OSiR¹⁶ ₃, --SiR¹⁶ ₃ or PR¹⁶ ₂ radical, inwhich R¹⁶ is a halogen atom, a C₁ -C₁₀ -alkyl group or a C₆ -C₁₀ -arylgroup, or adjacent radicals R⁴ to R¹², together with the atomsconnecting them, form one or more aromatic or aliphatic rings, or theradicals R⁵ and R⁸ or R¹², together with the atoms connecting them, forman aromatic or aliphatic ring, ##STR20## ═BR¹⁴, ═AlR¹⁴, --Ge--, --O--,--S--, ═SO, ═SO₂, ═NR¹⁴, ═CO, ═PR¹⁴ or ═P(O)R¹⁴, where R¹⁴ and R¹⁵ areidentical or different and are a hydrogen atom, a halogen atom, a C₁-C₁₀ -alkyl group, a C₁ -C₁₀ -fluoroalkyl group, a C₁ -C₁₀ -alkoxygroup, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀ -fluoroaryl group, a C₆ -C₁₀-aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₇ -C₄₀ -alkylaryl group or a C₈ -C₄₀ -arylalkenyl group, or R¹⁴ andR¹⁵, in each case together with atoms connecting them, form one or morerings, and M² is silicon, germanium or tin.
 6. The compound as claimedin claim 1, wherein M¹ is zirconium, R¹³ contains M² which is siliconand R¹ and R² are identical or different and are a C₁ -C₁₀ -alkyl group.7. The compound as claimed in claim 6, whereinR¹³ is --R¹⁴ M² R¹⁵ --,R¹⁴ and R¹⁵ are C₁ -alkyl and M² is silicon.
 8. The compound as claimedin claim 7, wherein R³ is a C₁ -alkyl.
 9. The compound as claimed inclaim 2, wherein M¹ is zirconium, R¹³ contains M² which is silicon andR¹ and R² are identical or different and are halogen atoms or a C₁ -C₁₀-alkyl group.
 10. The compound as claimed in claim 9, whereinR¹ and R²are a chlorine atom, R¹³ is --R¹⁴ M² R¹⁵ -- and M² is silicon.
 11. Thecompound as claimed in claim 10, wherein R³ is a C₁ -alkyl.
 12. Thecompound as claimed in claim 3, whereinR¹ and R² are a chlorine atom,R¹³ is --R¹⁴ M² R¹⁵ --, R¹⁴ and R¹⁵ are C₁ -C₁₀ alkyl or C₆ -C₁₀ -aryland M² is silicon.
 13. The compound as claimed in claim 4, wherein M¹ iszirconium, R¹ and R² are identical or different and are halogen atoms ora C₁ -C₁₀ -alkyl group.
 14. The compound as claimed in claim 13,whereinR¹ and R² are a chlorine atom and R¹³ is --R¹⁴ M² R¹⁵ --.
 15. Thecompound as claimed in claim 5, wherein M¹ is zirconium, R¹³ contains M²which is silicon and R¹ and R² are identical or different and arehalogen atoms or a C₁ -C₁₀ -alkyl group.
 16. The compound as claimed inclaim 15, whereinR¹ and R² are a chlorine atom, R¹³ is --R¹⁴ M² R¹⁵ --and M² is silicon.
 17. A compound of the formula I as claimed in claim3, wherein, in the formula I,M¹ is zirconium or hafnium, R¹ and R² areidentical and are a C₁ -C₃ -alkyl group or a halogen atom, the radicalsR³ are identical and are a C₁ -C₄ -alkyl group R⁴ to R¹² are hydrogen ora C₁ -C₄ -alkyl group, and ##STR21## where M² is silicon or germaniumand R¹⁴ and R¹⁵ are identical or different and are a C₁ -C₄ -alkyl groupor a C₆ -C₁₀ -aryl group.
 18. A compound of the formula I as claimed inclaim 5, wherein, in the formula I,R⁴ and R⁷ are hydrogen, and R⁵, R⁶and R⁸ to R¹² are identical or different and are hydrogen or a C₁ -C₄-alkyl group.
 19. A compound of the formula I as claimed in claim 3,wherein, in formula I,M¹ is zirconium, R¹ and R² are identical and arechlorine, the radicals R³ are identical and are a C₁ -C₄ -alkyl group,R⁴ and R⁷ are hydrogen, R⁵, R⁶ and R⁸ to R¹² are identical or differentand are a C₁ -C₄ -alkyl group or hydrogen, and ##STR22## where M² issilicon and R¹⁴ and R¹⁵ are a C₁ -C₄ -alkyl group or a C₆ -C₁₀ -arylgroup.
 20. A compound of formula I as claimed in claim 5, wherein, inthe formula I,M¹ is zirconium, R¹ and R² are chlorine, the radicals R³are methyl, R⁴ to R¹² are hydrogen, and ##STR23## where M² is silicon,and R¹⁴ and R¹⁵ are identical or different and are methyl, ethyl,n-propyl, i-propyl or phenyl.